This is a maintenance PR.
With scheduling the next autodim_check on every tap, we can keep the device longer in standby mode. So we have more power savings.
The long story: The current version works like that:
Let's say I set the idle-time to 3 min and I need 2.5 min to read a page.
Start at 0 min (next scheduled check is at/in 3 min)
Read and tap to turn page after 2.5 min (next scheduled check is at 3 min - in 0.5 min)
At 3 min there is a scheduled_check (wakeup) -> reschedule check in 3 min.
Read and tap to turn page after 2.5 min (no wakeup)
Then after 1 min there is a wakeup -> reschedule.
---> So I get an additional wakeup on every second page.
This PR solves the problem: During normal reading I don't get any wakeup during reading. (The only drawback is, that one function is unscheduled/scheduled on every tap, but that is no big deal).
