Both the compact and the fullpresentation variants of the applet had
an instance of a timer, and both were connected to the central "running"
flag. So if both variants had been created, there were 2 timers triggering
the decreasing of the seconds, and also firing off the command once done.

Moving the countdown timer (and at the same time also a timer for
delayed saving of the state, which had the same issue) to the central root
item fixes this.

BUG: 381173
FIXED-IN: 5.12.6

Applet still works as before on panel and background pane, now does proper
countdown in both cases.