Fix issue on conversation update

lib/helpers/conversations_helper.dart

@@ -58,7 +58,14 @@ class ConversationsHelper {
 
     final response = await request.exec();
 
-    return response.code == 200;
+    if(response.code != 200)
+      return false;
+
+    //Delete old conversation entry from the database
+    await _conversationsDatabaseHelper.delete(settings.id);
+
+    // Success
+    return true;
   }
 
   /// Delete a conversation specified by its [id]

lib/helpers/database/model_database_helper.dart

@@ -46,6 +46,17 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
     return null;
   }
 
+  /// Delete an entry from the database with a specified [id]
+  ///
+  /// Return true if at least one entry was deleted / false else
+  Future<bool> delete(int id) async {
+    return await (await DatabaseHelper.get()).delete(
+      tableName(),
+      where: '${BaseTableContract.C_ID} = ?',
+      whereArgs: [id],
+    ) > 0;
+  }
+
   /// Get all the entries from the table
   Future<List<T>> getAll() async {
     List<Map> maps = await (await DatabaseHelper.get()).query(tableName());