Solution Build/Clean/Rebuild on Solutions open from Solution filters runs on the original solution

Type: Bug

## Issue Description ##

Solution Build/Clean/Rebuild on Solutions open from Solution filters runs on the original solution (sln file) instead of the slnf file

## Steps to Reproduce ##

```
dotnet new sln -n MySolution
dotnet new console -n MyApp
dotnet sln MySolution.sln add MyApp/MyApp.csproj
dotnet new classlib -n MyLib
dotnet sln MySolution.sln add MyLib/MyLib.csproj
slnf-gen MySolution.sln --exclude '**/MyLib*'
```

Open the `MySolution.slnf`
Build

## Expected Behavior ##

Build runs on the MySolution.slnf

## Actual Behavior ##

Build runs on MySolution.sln

## Logs ##

```

dotnet build /Users/marco/Dev/test-solution/MySolution.sln --no-incremental /property:GenerateFullPaths=true /consoleloggerparameters:NoSummary /p:Configuration=Debug /p:Platform="Any CPU"
C# extension build result service is available.
Determining projects to restore...
All projects are up-to-date for restore.
MyLib -> /Users/marco/Dev/test-solution/MyLib/bin/Debug/net9.0/MyLib.dll
MyApp -> /Users/marco/Dev/test-solution/MyApp/bin/Debug/net9.0/MyApp.dll
* Terminal will be reused by tasks, press any key to close it.
```

### C# log ###
Activating task providers dotnet

### C# LSP Trace Logs ###

non

## Environment information ##

**VSCode version**: 1.101.1
**C# Extension**: 2.80.16
**Using OmniSharp**: false

Dotnet Information
.NET SDK:
Version: 9.0.300
Commit: 15606fe0a8
Workload version: 9.0.300-manifests.c678e91b
MSBuild version: 17.14.5+edd3bbf37

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.5
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.300/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.5
Architecture: arm64
Commit: e36e4d1a8f

.NET SDKs installed:
6.0.427 [/usr/local/share/dotnet/sdk]
8.0.407 [/usr/local/share/dotnet/sdk]
9.0.300 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.35 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.18 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.8 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.14 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.35 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.18 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.8 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.11 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.14 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
x64 [/usr/local/share/dotnet/x64]
registered at [/etc/dotnet/install_location_x64]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Code Extensions

|Extension|Author|Version|Folder Name|
|---|---|---|---|
|codespaces|GitHub|1.17.3|github.codespaces-1.17.3|
|csdevkit|ms-dotnettools|1.20.35|ms-dotnettools.csdevkit-1.20.35-darwin-arm64|
|csharp|ms-dotnettools|2.80.16|ms-dotnettools.csharp-2.80.16-darwin-arm64|
|duplicate-finder|tlevesque2|0.0.6|tlevesque2.duplicate-finder-0.0.6|
|EditorConfig|EditorConfig|0.17.4|editorconfig.editorconfig-0.17.4|
|gitignore|codezombiech|0.10.0|codezombiech.gitignore-0.10.0|
|hammerspoon|virgilsisoe|0.5.2|virgilsisoe.hammerspoon-0.5.2|
|html-preview-vscode|george-alisson|0.2.5|george-alisson.html-preview-vscode-0.2.5|
|identical-sublime-monokai-csharp-theme-colorizer|maximetinu|1.2.3|maximetinu.identical-sublime-monokai-csharp-theme-colorizer-1.2.3|
|lua|sumneko|3.14.0|sumneko.lua-3.14.0-darwin-arm64|
|opa|tsandall|0.19.0|tsandall.opa-0.19.0|
|prettier-vscode|esbenp|11.0.0|esbenp.prettier-vscode-11.0.0|
|rainbow-csv|mechatroner|3.19.0|mechatroner.rainbow-csv-3.19.0|
|sarif-viewer|MS-SarifVSCode|3.4.5|ms-sarifvscode.sarif-viewer-3.4.5|
|shell-format|foxundermoon|7.2.5|foxundermoon.shell-format-7.2.5|
|supermaven|Supermaven|1.1.12|supermaven.supermaven-1.1.12-darwin-arm64|
|text-power-tools|qcz|1.51.0|qcz.text-power-tools-1.51.0|
|unique-lines|bibhasdn|1.0.0|bibhasdn.unique-lines-1.0.0|
|vscode-azurefunctions|ms-azuretools|1.17.3|ms-azuretools.vscode-azurefunctions-1.17.3|
|vscode-azureresourcegroups|ms-azuretools|0.10.13|ms-azuretools.vscode-azureresourcegroups-0.10.13|
|vscode-dotnet-runtime|ms-dotnettools|2.3.5|ms-dotnettools.vscode-dotnet-runtime-2.3.5|
|vscode-eslint|dbaeumer|3.0.10|dbaeumer.vscode-eslint-3.0.10|
|vscode-html-css|ecmel|2.0.13|ecmel.vscode-html-css-2.0.13|
|vscode-kubernetes-tools|ms-kubernetes-tools|1.3.24|ms-kubernetes-tools.vscode-kubernetes-tools-1.3.24|
|vscode-markdownlint|DavidAnson|0.60.0|davidanson.vscode-markdownlint-0.60.0|
|vscode-mocha-test-runner|cstechnologies|0.3.3|cstechnologies.vscode-mocha-test-runner-0.3.3|
|vscode-regolint|plex|0.2.0|plex.vscode-regolint-0.2.0|
|vscode-yaml|redhat|1.18.0|redhat.vscode-yaml-1.18.0|
|vscodeintellicode-csharp|ms-dotnettools|2.2.3|ms-dotnettools.vscodeintellicode-csharp-2.2.3-darwin-arm64|
|vulnerability-extension|devprod|1.2025.619002|devprod.vulnerability-extension-1.2025.619002-darwin-arm64|
|xml|DotJoshJohnson|2.5.1|dotjoshjohnson.xml-2.5.1|;

Extension version: 2.80.16
VS Code version: Code 1.101.1 (18e3a1ec544e6907be1e944a94c496e302073435, 2025-06-18T13:35:12.605Z)
OS version: Darwin arm64 24.5.0
Modes:

System Info

|Item|Value|
|---|---|
|CPUs|Apple M2 Pro (12 x 2400)|
|GPU Status|2d_canvas: enabled
canvas_oop_rasterization: enabled_on
direct_rendering_display_compositor: disabled_off_ok
gpu_compositing: enabled
multiple_raster_threads: enabled_on
opengl: enabled_on
rasterization: enabled
raw_draw: disabled_off_ok
skia_graphite: enabled_on
video_decode: enabled
video_encode: enabled
webgl: enabled
webgl2: enabled
webgpu: enabled
webnn: disabled_off|
|Load (avg)|5, 8, 12|
|Memory (System)|32.00GB (0.14GB free)|
|Process Argv||
|Screen Reader|no|
|VM|0%|