chat-hook: clear all subscriptions on watch-nack
We would remove the entry from state, but not clean up its mailbox subscription.
::
[%backlog @ @ @ *]
=/ pax `path`(oust [(dec (lent t.wir)) 1] `(list @ta)`t.wir)
- =. synced (~(del by synced) pax)
- :_ state
- :- [%give %fact [/synced]~ %chat-hook-update !>([%initial synced])]
- %. ~
+ %. (poke-chat-hook-action %remove pax)
%- slog
:* leaf+"chat-hook failed subscribe on {(spud pax)}"
leaf+"stack trace:"
