Fix unused imports in HTTP client files

- Removed `Awaitable`, `cast`, and `BaseRequestExecutor` from `async_client.py`.
- Removed `cast` and `BaseRequestExecutor` from `client.py`.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: fderuiter

src/imednet/core/async_client.py

@@ -3,11 +3,11 @@
 from __future__ import annotations
 
 import logging
-from typing import Any, Awaitable, Dict, Optional, cast
+from typing import Any, Dict, Optional
 
 import httpx
 
-from imednet.core.http.executor import AsyncRequestExecutor, BaseRequestExecutor
+from imednet.core.http.executor import AsyncRequestExecutor
 from imednet.core.retry import RetryPolicy
 
 from .http_client_base import HTTPClientBase

src/imednet/core/client.py

@@ -13,11 +13,11 @@
 
 import logging
 from types import TracebackType
-from typing import Any, Dict, Optional, cast
+from typing import Any, Dict, Optional
 
 import httpx
 
-from imednet.core.http.executor import BaseRequestExecutor, SyncRequestExecutor
+from imednet.core.http.executor import SyncRequestExecutor
 from imednet.core.retry import RetryPolicy
 
 from .http_client_base import HTTPClientBase