Influx: Replace pre-calculated $__interval values for backend interpolation (#84975)

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

@@ -171,18 +171,26 @@ export default class InfluxDatasource extends DataSourceWithBackend<InfluxQuery,
   }
 
   applyTemplateVariables(query: InfluxQuery, scopedVars: ScopedVars): InfluxQuery & SQLQuery {
-    // We want to interpolate these variables on backend
-    const { __interval, __interval_ms, ...rest } = scopedVars || {};
+    const variables = scopedVars || {};
+
+    // We want to interpolate these variables on backend.
+    // The pre-calculated values are replaced withe the variable strings.
+    variables.__interval = {
+      value: '$__interval',
+    };
+    variables.__interval_ms = {
+      value: '$__interval_ms',
+    };
 
     if (this.version === InfluxVersion.Flux) {
       return {
         ...query,
-        query: this.templateSrv.replace(query.query ?? '', rest), // The raw query text
+        query: this.templateSrv.replace(query.query ?? '', variables), // The raw query text
       };
     }
 
     if (this.version === InfluxVersion.SQL || this.isMigrationToggleOnAndIsAccessProxy()) {
-      query = this.applyVariables(query, rest);
+      query = this.applyVariables(query, variables);
       if (query.adhocFilters?.length) {
         const adhocFiltersToTags: InfluxQueryTag[] = (query.adhocFilters ?? []).map((af) => {
           const { condition, ...asTag } = af;