fix(test): fix incorrect use of async warnings

What does this merge request do and why?

This MR fixes the incorrect mock object that cause warnings in test

sys:1: RuntimeWarning: coroutine 'AsyncMockMixin._execute_mock_call' was never awaited

Resolves #528 (closed)

How to set up and validate locally

1. Run make test to see the warning on main branch.

   sys:1: RuntimeWarning: coroutine 'async_client_factory.<locals>.create' was never awaited                                                 
   RuntimeWarning: Enable tracemalloc to get the object allocation traceback      

2. Check out to this merge request's branch.
3. Run make test to see the warning no longer show.

Merge request checklist

• Tests added for new functionality. If not, please raise an issue to follow up.
• Documentation added/updated, if needed.