AddTranslation now uses EditTranslation interface/modal.

src/message/translation_edit.py

@@ -91,7 +91,7 @@ class BinTranslation(DataChgClickMessage):
         model.translation = None
         
 
-class AddTranslation(DataChgClickMessage):
+class AddTranslation(EditTranslation):
     def handle_cluster_change(self, new_cluster_idx, _):
         # we need to cheat here
         # sense was actually given in constructor in third place