Errors when running .net generate assets to build .vscode folder

## Issue Description ##

For a hosted Blazor WebAssembly solution folder or **`Server`** project folder of the solution:

* Extension isn't offering to automatically add build and debug assets.
* Can't add `.vscode` assets manually.

Other issues:

* Similar to https://github.com/OmniSharp/omnisharp-vscode/issues/3176 (but not with the same cause, there's no apparent denial of writing to a path).
* Possibly similar to https://github.com/OmniSharp/omnisharp-vscode/issues/4493.

cc: @captainsafia

Cross-reference ASP.NET Core docs issue that I'm working that pertains to this process: https://github.com/dotnet/AspNetCore.Docs/issues/22234

## Steps to Reproduce ##

1. Create a hosted Blazor WebAssembly solution (`dotnet new blazorwasm -ho`).
2. Open the solution's folder (or the **`Server`** project folder). The extension doesn't offer to add the build and debug assets.
3. Attempt manual add of the assets with: **View** > **Command Palette** followed by **.NET: Generate Assets for Build and Debug**.
4. Notification appears:

> Could not locate .NET Core project. Assets were not generated.

The notification appears either trying to add the assets to the solution's folder or the **`Server`** project's folder.

## Expected Behavior ##

`.vscode` folder with `launch.json` and `tasks.json`, possibly with a prompt to add for the **`Server`** project if the solution's folder is opened in VSC.

## Actual Behavior ##

Error when attempting manual add:

> Could not locate .NET Core project. Assets were not generated.

## Logs ##

### OmniSharp log ###

Starting OmniSharp server at 5/7/2021, 7:54:50 PM
Target: c:\Users\XXXXX\Desktop\BlazorWebAssemblySignalRApp\Server

OmniSharp server started.
Path: c:\Users\XXXXX\.vscode\extensions\ms-dotnettools.csharp-1.23.11\.omnisharp\1.37.8\OmniSharp.exe
PID: 6856

[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Cake, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.DotNetTest, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Host, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.MSBuild, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Roslyn, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Roslyn.CSharp, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Script, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[dbug]: OmniSharp.CompositionHostBuilder
Loaded OmniSharp.Shared, Version=1.37.0.0, Culture=neutral, PublicKeyToken=null
[info]: OmniSharp.Stdio.Host
Starting OmniSharp on Windows 6.2.9200.0 (x64)
[info]: OmniSharp.Services.DotNetCliService
DotNetPath set to dotnet
[dbug]: OmniSharp.CompositionHostBuilder
.NET SDK requires MSBuild instances version 16.3 or higher
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Located 2 MSBuild instance(s)
1: Visual Studio Enterprise 2019 16.9.31205.134 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin"
2: StandAlone 16.9.0 - "c:\Users\XXXXX\.vscode\extensions\ms-dotnettools.csharp-1.23.11\.omnisharp\1.37.8\.msbuild\Current\Bin"
[dbug]: OmniSharp.CompositionHostBuilder
MSBuild instance Visual Studio Enterprise 2019 16.9.31205.134 scored at 2
[dbug]: OmniSharp.CompositionHostBuilder
MSBuild instance StandAlone 16.9.0 scored at 1
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.Utilities.Core.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.Tasks.Core.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.Framework.dll' (name-only).
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Registered MSBuild instance: Visual Studio Enterprise 2019 16.9.31205.134 - "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin"
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.Build.Utilities.Core, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.Utilities.Core.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.Framework.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.Build, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.dll' (name-only).
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.CodeAnalysis.VisualBasic.Workspaces, Version=3.10.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
FAILURE: Could not locate 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.CodeAnalysis.VisualBasic.Workspaces.dll'.
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.CodeAnalysis.VisualBasic.Features, Version=3.10.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
FAILURE: Could not locate 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.CodeAnalysis.VisualBasic.Features.dll'.
[dbug]: OmniSharp.WorkspaceInitializer
Starting with OmniSharp options: {"RoslynExtensionsOptions":{"EnableDecompilationSupport":false,"EnableAnalyzersSupport":false,"EnableImportCompletion":false,"DocumentAnalysisTimeoutMs":10000,"LocationPaths":null},"FormattingOptions":{"OrganizeImports":false,"EnableEditorConfigSupport":true,"NewLine":"\n","UseTabs":false,"TabSize":4,"IndentationSize":4,"SpacingAfterMethodDeclarationName":false,"SpaceWithinMethodDeclarationParenthesis":false,"SpaceBetweenEmptyMethodDeclarationParentheses":false,"SpaceAfterMethodCallName":false,"SpaceWithinMethodCallParentheses":false,"SpaceBetweenEmptyMethodCallParentheses":false,"SpaceAfterControlFlowStatementKeyword":true,"SpaceWithinExpressionParentheses":false,"SpaceWithinCastParentheses":false,"SpaceWithinOtherParentheses":false,"SpaceAfterCast":false,"SpacesIgnoreAroundVariableDeclaration":false,"SpaceBeforeOpenSquareBracket":false,"SpaceBetweenEmptySquareBrackets":false,"SpaceWithinSquareBrackets":false,"SpaceAfterColonInBaseTypeDeclaration":true,"SpaceAfterComma":true,"SpaceAfterDot":false,"SpaceAfterSemicolonsInForStatement":true,"SpaceBeforeColonInBaseTypeDeclaration":true,"SpaceBeforeComma":false,"SpaceBeforeDot":false,"SpaceBeforeSemicolonsInForStatement":false,"SpacingAroundBinaryOperator":"single","IndentBraces":false,"IndentBlock":true,"IndentSwitchSection":true,"IndentSwitchCaseSection":true,"IndentSwitchCaseSectionWhenBlock":true,"LabelPositioning":"oneLess","WrappingPreserveSingleLine":true,"WrappingKeepStatementsOnSingleLine":true,"NewLinesForBracesInTypes":true,"NewLinesForBracesInMethods":true,"NewLinesForBracesInProperties":true,"NewLinesForBracesInAccessors":true,"NewLinesForBracesInAnonymousMethods":true,"NewLinesForBracesInControlBlocks":true,"NewLinesForBracesInAnonymousTypes":true,"NewLinesForBracesInObjectCollectionArrayInitializers":true,"NewLinesForBracesInLambdaExpressionBody":true,"NewLineForElse":true,"NewLineForCatch":true,"NewLineForFinally":true,"NewLineForMembersInObjectInit":true,"NewLineForMembersInAnonymousTypes":true,"NewLineForClausesInQuery":true},"FileOptions":{"SystemExcludeSearchPatterns":["**/node_modules/**/*","**/bin/**/*","**/obj/**/*","**/.git/**/*","**/.git","**/.svn","**/.hg","**/CVS","**/.DS_Store"],"ExcludeSearchPatterns":[]},"RenameOptions":{"RenameOverloads":false,"RenameInStrings":false,"RenameInComments":false},"ImplementTypeOptions":{"InsertionBehavior":null,"PropertyGenerationBehavior":null},"Plugins":{"LocationPaths":null}}
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpFormattingWorkspaceOptionsProvider, Order: 0
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.Completion.CompletionOptionsProvider, Order: 0
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.RenameWorkspaceOptionsProvider, Order: 100
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.ImplementTypeWorkspaceOptionsProvider, Order: 110
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.BlockStructureWorkspaceOptionsProvider, Order: 140
[info]: OmniSharp.Cake.CakeProjectSystem
Detecting Cake files in 'c:\Users\XXXXX\Desktop\BlazorWebAssemblySignalRApp\Server'.
[info]: OmniSharp.Cake.CakeProjectSystem
Could not find any Cake files
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Attempting to resolve 'Microsoft.Build'
[dbug]: OmniSharp.MSBuild.Discovery.MSBuildLocator
SUCCESS: Resolved to 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Build.dll' (name-only).
[dbug]: OmniSharp.MSBuild.ProjectSystem
MSBuild environment:
Mode: VisualStudio
RunningTests: False
RunningInVisualStudio: False
MSBuildToolsDirectory32: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin
MSBuildToolsDirectory64: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\amd64
MSBuildSDKsPath: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Sdks
CurrentMSBuildConfigurationFile: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\MSBuild.exe.config
CurrentMSBuildExePath: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\MSBuild.exe
CurrentMSBuildToolsDirectory: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin
VisualStudioInstallRootDirectory: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise
MSBuildExtensionsPath: C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild

[info]: OmniSharp.MSBuild.ProjectSystem
Skip loading projects listed in solution file or under target directory because MsBuild:LoadProjectsOnDemand is true.
[info]: OmniSharp.Script.ScriptProjectSystem
Detecting CSX files in 'c:\Users\XXXXX\Desktop\BlazorWebAssemblySignalRApp\Server'.
[info]: OmniSharp.Script.ScriptProjectSystem
Could not find any CSX files
[info]: OmniSharp.WorkspaceInitializer
Configuration finished.
[info]: OmniSharp.Stdio.Host
Omnisharp server running using Stdio at location 'c:\Users\XXXXX\Desktop\BlazorWebAssemblySignalRApp\Server' on host 14288.
[dbug]: OmniSharp.Stdio.Host
************ Request ************
{
"Type": "request",
"Seq": 6,
"Command": "/projects"
}
[dbug]: OmniSharp.Stdio.Host
************ Request ************
{
"Type": "request",
"Seq": 5,
"Command": "/projects"
}
[dbug]: OmniSharp.Stdio.Host
************ Response ************
{
"Request_seq": 6,
"Command": "/projects",
"Running": true,
"Success": true,
"Message": null,
"Body": {
"MsBuild": {
"SolutionPath": null,
"Projects": []
},
"Script": {
"Projects": []
}
},
"Seq": 49,
"Type": "response"
}
[dbug]: OmniSharp.Stdio.Host
************ Response ************
{
"Request_seq": 5,
"Command": "/projects",
"Running": true,
"Success": true,
"Message": null,
"Body": {
"MsBuild": {
"SolutionPath": null,
"Projects": []
},
"Script": {
"Projects": []
}
},
"Seq": 50,
"Type": "response"
}
[dbug]: OmniSharp.Stdio.Host
************ Request ************
{
"Type": "request",
"Seq": 7,
"Command": "/projects"
}
[dbug]: OmniSharp.Stdio.Host
************ Response ************
{
"Request_seq": 7,
"Command": "/projects",
"Running": true,
"Success": true,
"Message": null,
"Body": {
"MsBuild": {
"SolutionPath": null,
"Projects": []
},
"Script": {
"Projects": []
}
},
"Seq": 54,
"Type": "response"
}
[dbug]: OmniSharp.Stdio.Host
************ Request ************
{
"Type": "request",
"Seq": 8,
"Command": "/projects"
}
[dbug]: OmniSharp.Stdio.Host
************ Response ************
{
"Request_seq": 8,
"Command": "/projects",
"Running": true,
"Success": true,
"Message": null,
"Body": {
"MsBuild": {
"SolutionPath": null,
"Projects": []
},
"Script": {
"Projects": []
}
},
"Seq": 57,
"Type": "response"
}

### C# log ###
Post the output from Output-->C# here

## Environment information ##

**VSCode version**: 1.56.0
**C# Extension**: 1.23.11

Dotnet Information
.NET SDK (reflecting any global.json):
Version: 5.0.202
Commit: db7cc87d51

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19041
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\5.0.202\

Host (useful for support):
Version: 5.0.5
Commit: 2f740adc14

.NET SDKs installed:
3.1.302 [C:\Program Files\dotnet\sdk]
5.0.202 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

Visual Studio Code Extensions

|Extension|Author|Version|
|---|---|---|
|code-spell-checker|streetsidesoftware|1.10.2|
|csharp|ms-dotnettools|1.23.11|
|DocFX|ms-docfx|0.1.3|
|docs-article-templates|docsmsft|0.2.11|
|docs-authoring-pack|docsmsft|0.1.13|
|docs-build|ceapex|0.1.24|
|docs-build|docsmsft|0.3.4|
|docs-images|docsmsft|0.0.9|
|docs-linting|docsmsft|0.0.7|
|docs-markdown|docsmsft|0.2.90|
|docs-metadata|docsmsft|1.0.6|
|docs-preview|docsmsft|0.3.57|
|docs-scaffolding|docsmsft|0.0.7|
|docs-yaml|docsmsft|0.2.6|
|js-debug-nightly|ms-vscode|2021.5.617|
|LinkCheckMD|blackmist|0.3.1|
|powershell|ms-vscode|2021.2.2|
|status-bar-tasks|GuardRex|0.3.0|
|vscode-markdownlint|DavidAnson|0.40.4|
|vscode-yaml|redhat|0.18.0|;