qr timeout - cancel in IDLE mode

Fotobox.py

@@ -277,7 +277,9 @@ class Fotobox:
     def _set_state(self, new_state: State):
         print(new_state)
         self._state = new_state
-        if new_state == State.COUNTDOWN:
+        if new_state == State.IDLE:
+            self._qr_timer.cancel()
+        elif new_state == State.COUNTDOWN:
             led_border(True)
             self._countdown_timer.restart()
         elif new_state == State.SHOOTING:

timer.py

@@ -32,6 +32,9 @@ class Timer:
             if self._callback:
                 self._callback()
 
+    def cancel(self):
+        self._enabled = False
+
     def current(self):
         return self._current