fix: Adjust target frameworks to only include available targets when creating new code library

[Acissathar]

PR Details

Currently trying to add a new code library project via the stride editor, results in an error:

Rather than try to build everything, only do what's currently available. Adding a new library now compiles as expected with no errors without having UWP or Android workloads for example.

Related Issue

#2154

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have built and run the editor to try this change out.

[Acissathar]

@dotnet-policy-service agree

[Doprez]

I honestly think the target could just be net8 in the future and let the package creator add platform specific parts after but this looks good to me.

[Eideren]

Thanks !