fixup! 🐛(backend) email invite in receivers language

E-mails sent for granting access are sent in the receiving users language. Falling back to system default language.

Co-authored-by: Samuel Paccoud <sampaccoud@users.noreply.github.com>

Author: rvveber

src/backend/core/tests/documents/test_api_document_invitations.py

@@ -419,7 +419,7 @@ def test_api_document_invitations_create_privileged_members(
 
 def test_api_document_invitations_create_email_from_senders_language():
     """
-    The email generated is from the language set on the sending user
+    When inviting on a document a user who does not exist yet in our database, the invitation email should be sent in the language of the sending user.
     """
     user = factories.UserFactory(language="fr-fr")
     document = factories.DocumentFactory()