Handle missing cases in CollectAnnotatedSymbolsPsiVisitor

[jaschdoc]

I studied the structure of PsiAnnotation a bit further and found what is hopefully an exhaustive solution.

Related to #2816

[bcorso]

Why not crash for null and PsiType?

Do you have examples what code leads to these cases?

[bcorso]

In particular, I'm curious if you've actually hit issues with this or if this is just to preemptively handle these cases in case they happen. Note that I don't think we technically need to handle every case exhaustively since our visitor itself skips a lot cases we don't care about. Especially, after #2863 where you improve the skip logic, I would be curious if we need to handle null and PsiType. If we don't have explicit failure cases for these then I would lean towards just crashing until someone reports a case and we can investigate the specific issue.

[jaschdoc]

This case was observed when returning an annotation as a default value for another annotation, e.g.,

public @interface JavaAnnotationWithDefaults {
    OtherAnnotation otherAnnotationVal() default @OtherAnnotation("def");
}

See annotationValue_java.kt. In this example, the default value for otherAnnotationVal is @OtherAnnotation("def")

[bcorso]

Thanks!

[bcorso]

LGTM, thanks!