When Sonarr's "Unmonitor Deleted Episodes" is enabled, deleted files cause episodes to be
unmonitored while the season stays monitored. Re-requesting sets season.monitored = true, but Sonarr
only cascades to episodes on state change. Since the season is already monitored, episodes stay
unmonitored and searches find nothing. Now explicitly re-monitors episodes for requested seasons
before triggering a search.
fix#2309