[release/6.0] Emit diagnostics & exceptions for sourcegen handling init-only properties & JsonInclude attributes#59097

Anipik merged 4 commits intorelease/6.0dotnet/runtime:release/6.0from

backport/pr-58993-to-release/6.0dotnet/runtime:backport/pr-58993-to-release/6.0Copy head branch name to clipboard