Relay with HSDir flag but no DirPort fail to respond to BEGIN_DIR

Because of #14202 (moved), directory authorities now can assign HSDir flag to a relay without a DirPort. However, relays don't accept BEGIN_DIR cells if options->DirPort_set is set to 0 (see directory_permits_begindir_requests()).

This is very problematic right now because as I'm opening this bug, we currently have 4348 HSDir in the consensus but 1497 of them (34%) of them don't have a DirPort thus not working.

Unless all relay updates with the patch, this situation will continue thus we should maybe bring back the need for a DirPort to get the HSDir flag on the autority sides?