fix: Adjust the alerting class and add Grafana v9 support

Author: ZPascal

grafana_api/alerting.py

@@ -903,7 +903,7 @@ def test_backtest_rule(self, condition: str, data_query: list) -> dict:
             Exception: Unspecified error by executing the API call
 
         Returns:
-            api_call (dict): Returns the result of the specified datasource_uid rule
+            api_call (dict): Returns the result of the specified rule
         """
 
         if len(condition) != 0 and data_query != list():