fix(cloud): add overloads to L7 policy polling methods

The create and replace methods have @overload decorators for different action
types, but the create_and_poll and replace_and_poll methods were missing the
corresponding overloads, causing pyright type errors when calling the base
methods.

This adds matching overloads to:
- L7PoliciesResource.create_and_poll
- L7PoliciesResource.replace_and_poll
- AsyncL7PoliciesResource.create_and_poll
- AsyncL7PoliciesResource.replace_and_poll

Author: algis-dumbris