[Feature Request] Revert breaking changes in JsonSerializerPrimitives

[keegan-caruso]

Is your feature request related to a problem? Please describe.

Many issues have been raised both in this repo, asp.net core, and Owin. Since this repo uses InternalsVisible, any APIs used across assemblies must be treated as public.

Describe the solution you'd like

Remove breaking changes between 7.x and 8.x Identity Model. The most problematic one is likely this: #2491

No breaking changes, only new APIs that get called, such that mismatched version still call a method that exists and doesn't have breaking behavioral changes.

Adding PublicAPI Analyzers to the 7x branch could help with understanding the API diffs.

Describe alternatives you've considered

Analyzers for mismatched version could help looking forward, but it isn't the right solution here.

Additional context

#2513 (comment)

cc @halter73

[keegan-caruso]

I think this needs to be fixed in 8x, but we also need to spend some time looking at our 8x -> 9x story for this class of issue and include explicit testing of mismatched 8x/9x versions.