Add external hook to /api/component_activities endpoint in dashboard snapshot router
Change is_active field of RayActivityResponse to take an enum RayActivityStatus instead of bool. This is a backward incompatible change, but should be ok because [dashboard] Add component_activities API #25996 wasn't included in any branch cuts. RayActivityResponse now supports informing when there was an error getting the activity observation and the reason.
Add /api/component_activities to the dashboard snapshot router which returns whether various Ray components are considered active
This currently only contains a response entry for drivers, but will add entries for other components on request as followups
