Implement ComplicationTypesUpdater.

The ComplicationTypesUpdater observes user settings for complication
types shown on the dream overlay, and pushes updates to the
DreamOverlayStateController.

Test: atest ComplicationTypesUpdaterTest
Test: locally on device by observing the complications update during
dream while changing complication types through adb command: adb shell settings put secure screensaver_enabled_complications [1,2,3..]
Fix: 217800355

Change-Id: I2d1e95c42a8092f79ef8db4128e970db96732509