Add callback to DozeParameters on alwaysOn change

Previously, the tuner callback would be called on the StatusBar before
DozeParameters, so the StatusBar would update with stale information.
Instead of relying on the ordering of the tuner, directly register a
callback to DozeParameters when the ALWAYS_ON setting is updated.

Test: manual, atest SystemUITests
Fixes: 186376450
Change-Id: Id3523ea33b451a2f565806cac636dfb59a125b30