[Clang][Sema] Fix attribute mismatch warning for ObjC class properties

If a class declares an instance property, and an inheritor class declares a class property with the same name, Clang Sema currently treats the latter as an overridden property, and compares the attributes of the two properties to check for a mismatch. The resulting diagnostics might be misleading, since neither of the properties actually overrides the another one.

rdar://86018435

Differential Revision: https://reviews.llvm.org/D116412