Set default for controls as enabled.

From this CL onwards, the default for controls is enabled (still not a
Setting).

The controls section in power menu and the new layout will only be used
if there's at least one app that can provide controls.

Test: manual
Bug: 149992619
Change-Id: I4e78735d642d24fe0080a0f0f4cbc58ffa2d5a94