Update the default wellbeing package config.

defaultWellbeingPackage is now deprecated and should not be used.
Instead, point all references to the new systemWellbeing config.

Bug: 233363529
Test: atest AmbientDisplayAlwaysOnPreferenceControllerTest
Test: atest DarkModeCustomBedtimePreferenceControllerTest
Test: atest DarkModeScheduleSelectorControllerTest
Test: atest WhenToDreamPreferenceControllerTest
Change-Id: Ia55ce505c5010e401ec0dc18a2fed41d3a692c7a