Settings: disable expanded desktop on power menu disable

If expanded desktop is enabled while the option for expanded desktop
setting is disabled, expanded desktop will remain active and the user
will not be able to disable expanded desktop without reenabling the
setting.

Change-Id: Ia91e34e5ce9f8680f64b81e5f79c2df6f0639bb2
Settings : Toggle expanded desktop for navbar

If entering the navbar screen with expanded desktop enabled, the navbar
is not shown hence hindering the ability to use the panel

This patchset addresses that by disabling expanded desktop upon entering,
and re-enabling upon exiting if it was previously enabled.

Patchset 2 : Fix state issues

Change-Id: I2776cf971f8899d30a25c0bf6b418793153555fc