Fixes and updates to LocationSettingsStore

1) Fix regression where defaults from system configurations were ignored.
2) Pass userId through listeners so that we don't need to recalculate
all location when a setting changes for a non-current user.

Test: CTS location tests
Bug: 144098502
Change-Id: If1bca907f1e5b3ccc27bb77398dd3a2ade65e2ef