fix(cpn): Only timers with active modes should be included in lists (#3956)

* disable timers with mode OFF

* fix isModeOff to reference mode not switch

* update model edit source lists when timer mode changed

* add timer mode test to reset function

* add timer mode test for Set and Reset functions

* change yaml special source TIMERx to Tmrx

companion/src/firmwares/timerdata.cpp

@@ -43,9 +43,9 @@ bool TimerData::isEmpty() const
           persistent == 0 /*&& pvalue == 0*/);
 }
 
-bool TimerData::isModeOff()
+bool TimerData::isModeOff() const
 {
-  return swtch == RawSwitch(SWITCH_TYPE_TIMER_MODE, 0);
+  return mode == TIMERMODE_OFF;
 }
 
 QString TimerData::nameToString(int index) const