[Copilot Search] Place internal testers in treatment group for metric testing (#54606)

Author: ashishkeshan

src/events/components/experiments/experiment.ts

@@ -54,6 +54,7 @@ export function shouldShowExperiment(
               ? routerQuery.feature.toLowerCase() === experiment.turnOnWithURLParam.toLowerCase()
               : false
           ) {
+            controlGroupOverride[experimentKey] = TREATMENT_VARIATION
             return true
           }
         }