SIENTIAPDE-1445

Refactor imports and enhance timestamp handling in API and test files

- Removed redundant import statements in api.py and prepare_worker.py for cleaner code.
- Updated timestamp format in test cases to include timezone information for consistency.
- Adjusted test configurations to align with new API structure for improved accuracy in data handling.

scouter/utils/clients/pi_web_api_client.py

@@ -213,7 +213,6 @@ class PIWebAPIClient(SientiaMonitoring):
                 tags=core_labels,
             )
 
-
             status_code = c.getinfo(pycurl.RESPONSE_CODE)
             body = buffer.getvalue().decode('utf-8', errors='replace')