Fix bug with swiping up on dreams to dismiss.

Swiping up from the bottom of a dream should either show the bouncer,
or, if the device is unlocked, dismiss the dream. The unlocked case
wasn't working and the swipe was ignored.

Bug: 357160685
Test: atest BouncerFullscreenSwipeTouchHandlerTest
Test: atest BouncerSwipeTouchHandlerTest
Flag: EXEMPT bugfix

Change-Id: I5dac759bf51b21484df357000510fa7ecb8bc383