TF-3219 display limits of email recovery in a yellow banner and filter out invalid suggestions

lib/main/localizations/app_localizations.dart

@@ -1374,6 +1374,12 @@ class AppLocalizations {
         name: 'last7Days');
   }
 
+  String get last15Days {
+    return Intl.message(
+        'Last 15 days',
+        name: 'last15Days');
+  }
+
   String get fromMe {
     return Intl.message(
         'From me',
@@ -3678,6 +3684,14 @@ class AppLocalizations {
     );
   }
 
+  String recoverDeletedMessagesBannerContent(String period) {
+    return Intl.message(
+      'You can recover messages deleted during the past $period',
+      name: 'recoverDeletedMessagesBannerContent',
+      args: [period]
+    );
+  }
+
   String get deletionDate {
     return Intl.message(
       'Deletion date',