Introducing new variable to enable/disable shortcuts.

Widgets and shortcuts are two different entities but they are controlled
by same variable GO_DISABLE_WIDGETS. In this CL I have introduced a new
variable GO_DISABLE_SHORTCUTS to enable/disable widgets.

Test: Tested manually on device.
Bug: 236268654
Change-Id: Ib373b042fbfd0493e6345ef10e5631dbfd96b8c3