rusticl/queue: fix implicit flushing of queue dependencies

rusticl/queue: fix implicit flushing of queue dependencies

Needed by Davinci Resolve.

There are two parts to this fix:
1. flush dependencies also on flush, not just finish
2. move the dependency checking logic into Queue::flush as otherwise we
   miss required implicit flushes.

Fixes: 8616c0a52c7 ("rusticl/event: flush queues from dependencies")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: @LingMan <18294-LingMan@users.noreply.gitlab.freedesktop.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26053>
(cherry picked from commit 8cbb84dc428ff805abc514d810faebe64bb03cdb)