PackageReference in msbuild\custom-task-code-generation\AppSettingStronglyTyped is not working

### Issue description

The approaches used in the AppSettingStronglyTyped example no longer work for using NuGet packages in projects with MSBuild Tasks.
When creating a package containing MSBuild Tasks, you cannot use NuGet packages as in a regular ClassLibrary project; NuGet packages, or more precisely the dlls supplied with them, must be bundled with the final package.

To achieve these goals, AppSettingStronglyTyped uses `CopyProjectReferencesToPackage` Target:
https://github.com/dotnet/samples/blob/d51488ecd50cf8dc774bdb0e0e6e2044bbe5ba5e/msbuild/custom-task-code-generation/AppSettingStronglyTyped/AppSettingStronglyTyped/AppSettingStronglyTyped.csproj#L41-L48

However, `Microsoft.Extensions.DependencyInjection.dll` is not included in the final package.
I expect that after running `dotnet package` .nupkg will have `tasks\netstandard2.0\Microsoft.Extensions.DependencyInjection.dll`, but it doesn't. Which leads to an error loading the library during the build:
```
System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.
```

### Steps to reproduce
Sample to reproduce https://github.com/Tripletri/samples/pull/1, integration tests is falling on this commit.

### Other thoughts

Since `CopyProjectReferencesToPackage` use `ReferenceCopyLocalPathsReferenceCopyLocalPaths` and `@(ReferenceCopyLocalPaths) ` is always empty, this may relate to https://github.com/dotnet/sdk/issues/3662.

As a workaround, I simply commit the external DLLs, reference them with `` and manually copy them at build time.

First of all, I'm interested in how to achieve this use of PackageReference in projects with MSBuild Tasks, especially with multi-targeting, since manually managing dependencies for all target frameworks is a headache.

Thanks in advice

### Target framework
- [x] .NET Standard2.0

dotnet --info output

```console
.NET SDK:
Version: 8.0.101
Commit: 6eceda187b
Workload version: 8.0.100-manifests.0f7d8591

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19045
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\8.0.101\

.NET workloads installed:
Workload version: 8.0.100-manifests.0f7d8591
There are no installed workloads to display.

Host:
Version: 8.0.1
Architecture: x64
Commit: bf5e279d92

.NET SDKs installed:
2.1.202 [C:\Program Files\dotnet\sdk]
2.2.402 [C:\Program Files\dotnet\sdk]
3.1.426 [C:\Program Files\dotnet\sdk]
5.0.408 [C:\Program Files\dotnet\sdk]
6.0.321 [C:\Program Files\dotnet\sdk]
6.0.418 [C:\Program Files\dotnet\sdk]
7.0.115 [C:\Program Files\dotnet\sdk]
7.0.203 [C:\Program Files\dotnet\sdk]
8.0.100 [C:\Program Files\dotnet\sdk]
8.0.101 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.26 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

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

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

```