Arcade property paths are incompletely changed

[crummel]

In Arcade, we have conditional TFMs to build for net6.0 instead of net3.1 when building with DotNetBuildFromSource=true. However, these changes have failed to account for some places where the TFM is embedded into paths that need to be accessed during the build run - for instance,

arcade/src/Microsoft.DotNet.Arcade.Sdk/tools/BuildTasks.props

Lines 5 to 6 in 1c400a1

	<ArcadeSdkBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' != 'Core'">$(MSBuildThisFileDirectory)net472\Microsoft.DotNet.Arcade.Sdk.dll</ArcadeSdkBuildTasksAssembly>
	<ArcadeSdkBuildTasksAssembly Condition="'$(MSBuildRuntimeType)' == 'Core'">$(MSBuildThisFileDirectory)netcoreapp3.1\Microsoft.DotNet.Arcade.Sdk.dll</ArcadeSdkBuildTasksAssembly>

. There was a change made in main to account for one instance of this: 9ffc76a but this hasn't been backported yet and should be expanded to most places the TFM is embedded in a path.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[markwilkie]

Do you have any thoughts on who should do this work @crummel ?

[crummel]

I just sent out a meeting to discuss the related issue #7413 which I think we'll want to figure out first, I'll add you.