Revert "Implement showDesktopApps"

Revert submission 20653722

Reason for revert: DroidMonitor-triggered revert due to breakage <link to breakage in Quarterdeck>, bug b/262303930.
Reverted Changes: 
BUG: <breakage bug #>
I0435e07a2:Create controller for desktop prototype 2
I9907038ad:Implement move to desktop and fullscreen
Ic5de4d431:Implement showDesktopApps

Change-Id: Ia04d63dd0d9506b7b6d874883b5d0d69585b03ad