Update `addConventionAnnotationValues` so that `value` attributes do not override existing annotation values. The aligns the new `MergedAnnotations` API with the previous `AnnotatedElementUtils` logic. Closes gh-22703
Update `addConventionAnnotationValues` so that `value` attributes do not override existing annotation values. The aligns the new `MergedAnnotations` API with the previous `AnnotatedElementUtils` logic. Closes gh-22703