Revert multiple SDK updates.

[halter73]

This seems to fix multiple internal builds and avoids the following error when building in VS.

Error    CS8032    An instance of analyzer Microsoft.NET.Sdk.Razor.SourceGenerators.RazorSourceGenerator cannot be created from C:\github\aspnetcore\.dotnet\sdk\6.0.100-preview.7.21327.2\Sdks\Microsoft.NET.Sdk.Razor\source-generators\Microsoft.NET.Sdk.Razor.SourceGenerators.dll : Could not load type 'Microsoft.CodeAnalysis.IIncrementalGenerator' from assembly 'Microsoft.CodeAnalysis, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'

[halter73]

I'm still trying to figure out what the problem is and how to fix the internal build issues, but I want to have this ready as a backup if the fix is non-trivial.

[halter73]

This already passed an internal build https://dev.azure.com/dnceng/internal/_build/results?buildId=1209830&view=results

[JunTaoLuo]

In case we don't have other alternatives identified, we can check this in.

[JunTaoLuo]

Remember to revert this if you end up checking this in.

[captainsafia]

I assume the internal build issues are unrelated to the source generator change?

[halter73]

I assume the internal build issues are unrelated to any source gen stuff. We consistently see the following error when publishing successfully built assets.

BARBuildId : The term 'BARBuildId' is not recognized as the name of a cmdlet, function, script file, or operable program.

[dougbu]

@captainsafia see Teams conversation in Build channel. @halter73 is going back two SDK updates (your #33833 and @BrennanConroy's #33719) to get back to a known-good state while we let those w/ actual knowledge e.g. @rainersigwald @MattGal figure things out.

[captainsafia]

Yep. Sounds good.

avoids the following error when building in VS.

I'm working on tracking down this one.

[halter73]

Closing in favor of #33922