chore: Follow up other party has no keys

lib/pages/chat/send_file_dialog.dart

@@ -131,9 +131,15 @@ class SendFileDialogState extends State<SendFileDialog> {
       scaffoldMessenger.clearSnackBars();
     } catch (e) {
       scaffoldMessenger.clearSnackBars();
+      final theme = Theme.of(context);
       scaffoldMessenger.showSnackBar(
         SnackBar(
-          content: Text(e.toLocalizedString(widget.outerContext)),
+          backgroundColor: theme.colorScheme.errorContainer,
+          closeIconColor: theme.colorScheme.onErrorContainer,
+          content: Text(
+            e.toLocalizedString(widget.outerContext),
+            style: TextStyle(color: theme.colorScheme.onErrorContainer),
+          ),
           duration: const Duration(seconds: 30),
           showCloseIcon: true,
         ),

lib/utils/localized_exception_extension.dart

@@ -8,6 +8,7 @@ import 'package:http/http.dart';
 import 'package:matrix/encryption.dart';
 import 'package:matrix/matrix.dart';
 
+import 'package:fluffychat/utils/other_party_can_receive.dart';
 import 'uia_request_manager.dart';
 
 extension LocalizedExceptionExtension on Object {
@@ -34,6 +35,9 @@ extension LocalizedExceptionExtension on Object {
         _formatFileSize(exception.maxFileSize),
       );
     }
+    if (this is OtherPartyCanNotReceiveMessages) {
+      return L10n.of(context).otherPartyNotLoggedIn;
+    }
     if (this is MatrixException) {
       switch ((this as MatrixException).error) {
         case MatrixError.M_FORBIDDEN: