Add mobile registration and dispatch event for mobile postmessage dance

src/settings/Settings.tsx

@@ -876,6 +876,10 @@ export const SETTINGS: { [setting: string]: ISetting } = {
         supportedLevels: LEVELS_ACCOUNT_SETTINGS,
         default: null,
     },
+    "Registration.mobileRegistrationHelper": {
+        supportedLevels: [SettingLevel.CONFIG],
+        default: false,
+    },
     "autocompleteDelay": {
         supportedLevels: LEVELS_DEVICE_ONLY_SETTINGS_WITH_CONFIG,
         default: 200,