fix: fix flake8 complaint

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

software/src/app.py

@@ -196,8 +196,5 @@ class PlayerApp:
     def get_playlist_db(self):
         return self.playlist_db
 
-    def get_timer_manager(self):
-        return self.timer_manager
-
     def get_leds(self):
         return self.leds

software/src/webserver.py

@@ -33,7 +33,7 @@ def start_webserver(config_, app_):
     nfc = app.get_nfc()
     playlist_db = app.get_playlist_db()
     leds = app.get_leds()
-    timer_manager = app.get_timer_manager()
+    timer_manager = TimerManager()
 
 
 @webapp.before_request