Handle predicates without __name__ in waitForEvent timeouts

[kwy404]

When waitForEvent times out, it builds the error message from predicate.__name__. Callables such as functools.partial objects have no __name__, so instead of CallbackHandlerTimeoutError the caller got an AttributeError. This falls back to repr(predicate) in CallbackHandlerBase and the legacy CallbackHandler; the added test with a partial predicate fails before the change and passes after, and pyink is clean on the changed files.