Refactor code for consistency and readability

- Standardized string quotes across multiple files to use double quotes for consistency.
- Improved formatting of JSON dumps in mock data for better readability.
- Enhanced the structure of various functions and data definitions for clarity.
- Updated test cases to reflect changes in data structure and ensure accuracy.

dashboard/prometheus_utils/query.py

@@ -1,5 +1,4 @@
 import requests
-
 from watcher_visio.settings import PROMETHEUS_URL
 
 # Timeout for lightweight health check (seconds)