Set performance monitoring to false in App Store builds

Author: mokagio

Experiments/Experiments/DefaultFeatureFlagService.swift

@@ -39,6 +39,13 @@ public struct DefaultFeatureFlagService: FeatureFlagService {
             return buildConfig == .localDeveloper || buildConfig == .alpha
         case .wpcomSignup:
             return buildConfig == .localDeveloper || buildConfig == .alpha
+        case .performanceMonitoring,
+                .performanceMonitoringCoreData,
+                .performanceMonitoringFileIO,
+                .performanceMonitoringNetworking,
+                .performanceMonitoringViewController,
+                .performanceMonitoringUserInteraction:
+            return buildConfig != .appStore
         default:
             return true
         }