Fix alert not respecting can_acknowledge setting (#139483)

* fix(alert): check can_ack prior to acking

* fix(alert): add test for when can_acknowledge=False

* fix(alert): warn on can_ack blocking an ack

* Raise error when trying to acknowledge alert with can_acknowledge set to False

* Rewrite can_ack check as guard

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Make can_ack service error msg human readable because it will show up in the UI

* format with ruff

* Make pytest aware of service error when acking an unackable alert

---------

Co-authored-by: Franck Nijhof <frenck@frenck.nl>