Alerting: Modify endpoint for testing a datasource rule using the UID (#48070)

* Modify testing endpoint to expect the datasource UID

* Update docs

pkg/services/ngalert/api/tooling/definitions/testing.go

@@ -26,7 +26,7 @@ import (
 //     Responses:
 //       200: TestRuleResponse
 
-// swagger:route Post /api/v1/rule/test/{DatasourceID} testing RouteTestRuleConfig
+// swagger:route Post /api/v1/rule/test/{DatasourceUID} testing RouteTestRuleConfig
 //
 // Test a rule against external data source ruler
 //