Suppress ANN401 for methods annotated with typing_extensions.override

[sirrus233]

I believe this is a follow-on request from: #3952

Where that discussion landed was that it is reasonable to suppress ARG002 for overridden methods, since you cannot control the method signature. I think it follows that ANN401 should be suppressed as well, since if we cannot control the method signature we also cannot control the types, and it is impossible to narrow or remove Any in such cases.