Fix performance issues with 'cta-admin dr down' command
Summary
As explained in https://gitlab.cern.ch/cta/operations/-/issues/1695, there seems to be a problem with the cta-admin dr down command that is causing it to take a very long amount of time to complete.
It may be related to the recent change:
- 70cee9a4
- https://gitlab.cern.ch/cta/CTA/-/blame/main/frontend/common/AdminCmd.cpp?page=2#L1590-L1591
Steps to reproduce
Please check https://gitlab.cern.ch/cta/operations/-/issues/1695.