fix: add constants.ts back

ts/localization/constants.ts

@@ -0,0 +1,7 @@
+export enum LOCALE_DEFAULTS {
+  app_name = 'Session',
+  session_download_url = 'https://getsession.org/download',
+  gif = 'GIF',
+}
+
+export const rtlLocales = ['ar', 'fa', 'he', 'ps', 'ur'] as const;