Fix timer.cancel action fires timer.cancelled event even on canceled timers (#134507)

* Fixes https://github.com/home-assistant/core/issues/116105

* Fixes unit test in accordance to documentation

Timer needs to be active before it can be canceled

* Allow canceling of paused timers

* Add test for canceling/finishing already canceled/finished timers

* Add test for finishing a paused timer, this should not be possible

* Revert finish related tests

* Merge branch 'timer.cancelled_fix' of
git@github.com:rrooggiieerr/homeassistant-core.git into
timer.cancelled_fix

---------

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

homeassistant/components/timer/__init__.py

@@ -374,6 +374,9 @@ class Timer(collection.CollectionEntity, RestoreEntity):
     @callback
     def async_cancel(self) -> None:
         """Cancel a timer."""
+        if self._state == STATUS_IDLE:
+            return
+
         if self._listener:
             self._listener()
             self._listener = None

tests/components/timer/test_init.py

@@ -196,6 +196,12 @@ async def test_methods_and_events(hass: HomeAssistant) -> None:
             "event": EVENT_TIMER_CANCELLED,
             "data": {},
         },
+        {
+            "call": SERVICE_CANCEL,
+            "state": STATUS_IDLE,
+            "event": None,
+            "data": {},
+        },
         {
             "call": SERVICE_START,
             "state": STATUS_ACTIVE,