✨(backend) add document path and depth to accesses endpoint

The frontend requires this information about the ancestor document
to which each access is related. We make sure it does not generate
more db queries and does not fetch useless and heavy fields from
the document like "excerpt".

src/backend/core/models.py

@@ -1123,9 +1123,7 @@ class DocumentAccess(BaseAccess):
         if self.role == RoleChoices.OWNER:
             can_delete = role == RoleChoices.OWNER and (
                 # check if document is not root trying to avoid an extra query
-                # "document_path" is annotated by the viewset's list method
-                len(getattr(self, "document_path", "")) > Document.steplen
-                or not self.document.is_root()
+                self.document.depth > 1
                 or DocumentAccess.objects.filter(
                     document_id=self.document_id, role=RoleChoices.OWNER
                 ).count()