Add localization support for German, Spanish, French, and Italian

- Updated localization files for French, Croatian, Italian, Slovenian to include translations for German, Spanish, French, and Italian.
- Added new methods for handling drawing messages sent to the public channel in multiple languages.
- Enhanced the Contact model to identify public channels using a dedicated method.
- Implemented echo detection for public channel messages, including tracking and reporting of echoes.
- Updated BLE response handling to support echo detection and tracking of sent messages.
- Modified UI components to reflect new localization strings and echo statuses.

lib/l10n/app_localizations_it.dart

@@ -144,6 +144,18 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get croatian => 'Croato';
 
+  @override
+  String get german => 'Tedesco';
+
+  @override
+  String get spanish => 'Spagnolo';
+
+  @override
+  String get french => 'Francese';
+
+  @override
+  String get italian => 'Italiano';
+
   @override
   String get locationBroadcasting => 'Trasmissione Posizione';
 
@@ -387,6 +399,16 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get storedPermanently => 'Archiviato permanentemente nella stanza';
 
+  @override
+  String drawingsSentToPublicChannel(int count, String plural) {
+    return '$count disegno$plural mappa inviato al Canale Pubblico';
+  }
+
+  @override
+  String drawingsSharedToPublicChannel(int success, int total) {
+    return '$success/$total disegni condivisi sul Canale Pubblico';
+  }
+
   @override
   String get notConnectedToDevice => 'Non connesso al dispositivo';
 
@@ -1007,6 +1029,9 @@ class AppLocalizationsIt extends AppLocalizations {
   @override
   String get failed => 'Fallito';
 
+  @override
+  String get broadcast => 'Trasmissione';
+
   @override
   String get sarMarkerFoundPerson => 'Persona Trovata';