Fix jellyfin edge case scrobbling mess

Finally get to resolve scrobbling music from Jellyfin. This may lead to
other issues, in fact now videos seem to sometimes create duplicate
scrobbles. But music can be scrobbled now from Jellyfin web or Finamp
successfully.

vrobbler/apps/scrobbles/mixins.py

@@ -7,6 +7,8 @@ BNULL = {"blank": True, "null": True}
 
 
 class ScrobblableMixin(TimeStampedModel):
+    SECONDS_TO_STALE = 1600
+
     uuid = models.UUIDField(default=uuid4, editable=False, **BNULL)
     title = models.CharField(max_length=255, **BNULL)
     run_time = models.CharField(max_length=8, **BNULL)