Localizer: fix wrong replacement list -> ensure_list

This list was to cast the tuple, it can cause an AttributeError("'tuple' object has no attribute 'append'",)
error when this branch is used.

This is really an error code path, so that was unnoticed.

product/Localizer/MessageCatalog.py

@@ -60,7 +60,6 @@ from .interfaces import IMessageCatalog
 from .LanguageManager import LanguageManager
 from .LocalFiles import LocalDTMLFile
 from .utils import charsets, lang_negotiator, _
-from Products.ERP5Type.Utils import ensure_list
 
 
 ###########################################################################
@@ -312,7 +311,7 @@ class MessageCatalog(LanguageManager, ObjectManager, SimpleItem):
             if lang is None:
                 # Builds the list of available languages
                 # should the empty translations be filtered?
-                available_languages = ensure_list(self._languages)
+                available_languages = list(self._languages)
 
                 # Imagine that the default language is 'en'. There is no
                 # translation from 'en' to 'en' in the message catalog