Nullable enable Razor components

[jjonescz]

Fixes #7169.

The product change (d2ae625) is inspired by Razor Pages:

razor/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/src/RazorPageDocumentClassifierPass.cs

Line 96 in d7ad748

@class.Annotations[CommonAnnotations.NullableContext] = CommonAnnotations.NullableContext;

and MVC documents:

razor/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/src/MvcViewDocumentClassifierPass.cs

Line 70 in d7ad748

@class.Annotations[CommonAnnotations.NullableContext] = CommonAnnotations.NullableContext;

[jaredpar]

This PR has gotten pretty stale. Is it a PR that we need to be acitvely pushing on? If not can we move it to draft?

[333fred]

Clarified with @jaredpar that we're waiting on his feedback on the breaking change. He'll give it some thought.

[jjonescz]

@jaredpar ping :)

I ran our internal tests to verify there are no regressions in the projects we build there: https://dev.azure.com/dnceng/internal/_build/results?buildId=2391488&view=results

[jaredpar]

Sorry, I lost the thread here. Is this going to conflict with @chsienki upcoming FUSE changes. Both changes are doing massive baseline updates so curious if theyr'e going to conflict. If so need to figure out a merge order here.

[chsienki]

For the most part, when it comes to baselines its not too much hassle to merge, you just re-generate them as part of the merge process so they include both sets of changes.

[jaredpar]

Sounds good. I'm on board with pushing this forward.

[jjonescz]

@dotnet/razor-compiler for reviews, thanks

[jjonescz]

@dotnet/razor-compiler for a second review - it's a simple change although "multiplied" by all our baselines :) thanks