Update main toggle state in User Settings onResume()

The toggle state used to be set on creation and only changed onSwitchToggled(). But the state can also change when restrictions are applied from outside of settings, or when user is added with toggle being off by default.

This change updates the state during execution of onResume() in Users Settings, which also aligns with the update strategy of other Toggles on this Settings page.

Bug: 362706097
Test: atest MultiUserSwitchBarControllerTest
Flag: EXEMPT bugfix
Change-Id: I8a994b2e0ddb672362e69653374b87f85ae1548c