Queries: Fix debug logging of metrics queries (#83877)

fix log statements

pkg/services/query/query.go

@@ -306,13 +306,13 @@ func (s *ServiceImpl) parseMetricRequest(ctx context.Context, user identity.Requ
 			req.parsedQueries[ds.UID] = []parsedQuery{}
 		}
 
-		s.log.Debug("Processing metrics query", "query", query)
-
 		modelJSON, err := query.MarshalJSON()
 		if err != nil {
 			return nil, err
 		}
 
+		s.log.Debug("Processing metrics query", "query", string(modelJSON))
+
 		req.parsedQueries[ds.UID] = append(req.parsedQueries[ds.UID], parsedQuery{
 			datasource: ds,
 			query: backend.DataQuery{