Split PortraitOverviewStateTouchHelper for Go

Split out the logic in PortraitOverviewStateTouchHelper that is
dependent on the recents view implementation. This is done through a
separate helper class that we override on Go to stub out most of the
behavior.

This results in the Go version not supporting swipe transitions from
the recents state which is desired since we would otherwise risk
confusion over whether the swipe should go to the view or to the
transition (note that we will also take out the hotseat in this state).

Bug: 114136250
Test: Manual test NexusLauncher and l3goWithQuickstep
Test: Build l3goWithQuickstepIconRecents
Change-Id: I9b0e9c05171d279d03bbcb7f05344fa425f34b3e