Fix crash on fallback recents Go activity

Recents Go would crash when attempting to touch the fallback recents
activity since it's based off the base dragging activity in launcher
which assumes some touch controllers are initialized. As we leave
all touch input to hooks on the views themselves, we do not need touch
controllers and initialize an empty list instead.

Bug: 114136250
Test: Launch fallback recents activity, touch around
Change-Id: Ic136ace6f968d8c469c6f300daf4ee28fbde5e69