InfluxDB: metricFindQuery migration to backend (#44546)

* Send metricFindQuery to backend

* Added feature toggle

* Changed flag name

* metricFindQuery backend

* Added test for metricFindQuery backend parse

* Added test for show tag values

* Test for metricFindQueries

* Updated tests

* Put back comment

* Case insensitive in transformRows

* Check length ov value pair

* Sep tests

* Updated valuePair index

public/app/plugins/datasource/influxdb/datasource.ts

@@ -445,10 +445,11 @@ export default class InfluxDatasource extends DataSourceWithBackend<InfluxQuery,
   }
 
   async metricFindQuery(query: string, options?: any): Promise<MetricFindValue[]> {
-    if (this.isFlux) {
+    if (this.isFlux || (config.featureToggles.influxdbBackendMigration && this.access === 'proxy')) {
       const target: InfluxQuery = {
         refId: 'metricFindQuery',
         query,
+        rawQuery: true,
       };
       return lastValueFrom(
         super.query({