Elasticsearch: Fix where name of frame is set (#64233)

* Elasticsearch: Use displayName field for naming

* Change solution to frame.Name to be backward compatible

* Fix snapshot tests

* Use Time and Value for time and value fields

* Use variables from grafana-plugin-sdk-go for name

pkg/tsdb/elasticsearch/response_parser_frontend_test.go

@@ -61,18 +61,7 @@ func requireFloatAt(t *testing.T, expected float64, field *data.Field, index int
 }
 
 func requireTimeSeriesName(t *testing.T, expected string, frame *data.Frame) {
-	getField := func() *data.Field {
-		for _, field := range frame.Fields {
-			if field.Type() != data.FieldTypeTime {
-				return field
-			}
-		}
-		return nil
-	}
-
-	field := getField()
-	require.NotNil(t, expected, field.Config)
-	require.Equal(t, expected, field.Config.DisplayNameFromDS)
+	require.Equal(t, expected, frame.Name)
 }
 
 func TestRefIdMatching(t *testing.T) {