Add missing strings for expense statuses

lib/utils/i18n.dart

@@ -18,6 +18,8 @@ mixin LocalizationsProvider on LocaleCodeAware {
   static final Map<String, Map<String, String>> _localizedValues = {
     'en': {
       // STARTER: lang key - do not remove comment
+      'expense_status_4': 'Unpaid',
+      'expense_status_5': 'Paid',
       'recurring': 'Recurring',
       'ziptax_help':
           'Note: this feature requires a Zip-Tax API key to lookup US sales tax by address',