Move zen mode evaluation back into setConfig.

The process of setting zen mode during a config change was separated into two pieces because of a cross-lock held with AudioManager. To avoid having lock contention, it suffices to bring the ringer mode changes out to the handler while having the zen mode evaluations happen in one pass.

Also remove an unnecessary call to evaluateZenMode in onSystemReady (it's called right after cleanUpZenRules, which will already call setConfig -> evaluateZenMode).

Bug: 280333605
Test: ZenModeHelperTest
Change-Id: Icc7615e2d02fc8b83613687c8e2bed8e99fa9613