🐛(backend) add partial_update action to the abilities

partial_update action was missing for the permission.
So when we were patching the template,
it was not working.
This commit adds the partial_update action
to the abilities.

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

@@ -21,6 +21,7 @@ def test_api_documents_retrieve_anonymous_public():
         "abilities": {
             "destroy": False,
             "manage_accesses": False,
+            "partial_update": False,
             "retrieve": True,
             "update": False,
         },
@@ -60,6 +61,7 @@ def test_api_documents_retrieve_authenticated_unrelated_public():
         "abilities": {
             "destroy": False,
             "manage_accesses": False,
+            "partial_update": False,
             "retrieve": True,
             "update": False,
         },