Incorrect FallbackDir flag in Relay Search

The new FallbackDir list has to be updated. This process currently is an actual update in metrics-web code.

The file holding the list is: https://gitlab.torproject.org/tpo/network-health/metrics/website/-/blob/master/src/main/resources/web/js/rs/fallback_dir.js

There is a python script that updates the fallbackdir list: https://gitlab.torproject.org/tpo/network-health/metrics/website/-/blob/master/src/main/python/fallback_dir.py

We should find a way to automate this task in the metrics-web build process. Bonus point if this happens with CI.