fix: InstanceValuesInTestClassAnalyzer uses return instead of continue (#4859)

[thomhurst]

Summary

• Fix a bug in InstanceValuesInTestClassAnalyzer.AnalyzeOperation where a return statement inside a foreach loop exits the entire method instead of using continue to skip to the next field/property
• When iterating over fieldsAndProperties, if the assignment target's containing type doesn't match the test class, only the current iteration should be skipped -- not the entire analysis

Details

In TUnit.Analyzers/InstanceValuesInTestClassAnalyzer.cs around line 59, the foreach loop over fieldsAndProperties had a return; that would exit the AnalyzeOperation method entirely when the target symbol's containing type didn't match the test class. This has been changed to continue; so the loop properly continues checking the remaining fields and properties.

Closes #4859

Test plan

• Existing analyzer tests pass (the Do_Not_Flag_When_Not_Assigning_To_New_Class test covers this scenario)
• Project builds successfully with zero errors

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

The fix is correct: return inside a foreach loop was prematurely exiting the entire AnalyzeOperation method when an assignment target's containing type didn't match the test class, causing all remaining fields/properties to be skipped without analysis. Replacing it with continue is the right fix — it skips only the non-matching iteration and lets the loop proceed normally. Clean, minimal, and directly addresses the described bug.