The `Account._current_tenant` object is loaded by a database session (typically `db.session`) whose lifetime
is not aligned with the Account model instance. This misalignment causes a `DetachedInstanceError` to be raised
when accessing attributes of `Account._current_tenant` after the original session has been closed.
To resolve this issue, we now reload the tenant object with `expire_on_commit=False`, ensuring the tenant remains
accessible even after the session is closed.