InfluxDB: Fix parsing multiple tags on backend mode (#77340)

* Multiple tags separated by comma in the result

* A non-flaky unit test

pkg/tsdb/influxdb/influxql/response_parser.go

@@ -258,6 +258,7 @@ func buildFrameNameFromQuery(row models.Row, column string, frameName []byte, re
 		first := true
 		for k, v := range row.Tags {
 			if !first {
+				frameName = append(frameName, ',')
 				frameName = append(frameName, ' ')
 			} else {
 				first = false

pkg/tsdb/influxdb/influxql/response_parser_test.go

@@ -365,6 +365,46 @@ func TestInfluxdbResponseParser(t *testing.T) {
 		assert.Equal(t, "alias logins.count", result.Frames[1].Name)
 	})
 
+	t.Run("Influxdb response parser when multiple measurement in response", func(t *testing.T) {
+		response := `
+		{
+			"results": [
+				{
+					"series": [
+						{
+							"name": "cpu.upc",
+							"columns": ["time","mean"],
+							"tags": {
+								"datacenter": "America",
+								"cluster-name":   "Cluster"
+							},
+							"values": [
+								[111,222]
+							]
+						},
+						{
+							"name": "logins.count",
+							"columns": ["time","mean"],
+							"tags": {
+								"datacenter": "America",
+								"cluster-name":   "Cluster"
+							},
+							"values": [
+								[111,222]
+							]
+						}
+					]
+				}
+			]
+		}
+		`
+
+		query := models.Query{}
+		result := ResponseParse(prepare(response), 200, generateQuery(query))
+		assert.True(t, strings.Contains(result.Frames[0].Name, ","))
+		assert.True(t, strings.Contains(result.Frames[1].Name, ","))
+	})
+
 	t.Run("Influxdb response parser with alias", func(t *testing.T) {
 		response := `
 		{