NuGet packages are including Labs-Only Source Generators

[michael-hawker]

The NuGet packages we're outputting are including our Labs-only source generators:

This makes them unusable/consumable by others.

This is because they're being included in the Labs.MultiTarget.props file used by the library projects:

Labs-Windows/common/Labs.MultiTarget.props

Lines 42 to 48 in 6ed4315

	<!-- Source generator props -->
	<ItemGroup>
	<ProjectReference Include="$(RepositoryDirectory)\common\CommunityToolkit.Labs.Core.SourceGenerators.XamlNamedPropertyRelay\CommunityToolkit.Labs.Core.SourceGenerators.XamlNamedPropertyRelay.csproj"
	OutputItemType="Analyzer" ReferenceOutputAssembly="True" />
	<ProjectReference Include="$(RepositoryDirectory)\common\CommunityToolkit.Labs.Core.SourceGenerators\CommunityToolkit.Labs.Core.SourceGenerators.csproj"
	OutputItemType="Analyzer" ReferenceOutputAssembly="True" />
	</ItemGroup>

My current work is in this branch:
https://github.com/CommunityToolkit/Labs-Windows/tree/feature/sg-head-only

It wasn't working properly, but I may have fixed it...