Do not predictive back to translucent task, which could be trampoline.

Skip predictive back to translucent task, because it could be
trampoline task, and could be finish with current top task.

Also fix the check translucent condition for the previous activity, as
the previous activity does not require visibility when predicting,
there should check WindowState#hasWallpaper instead of showWallpaper.

Bug: 336149696
Test: atest BackNavigationControllerTests
Change-Id: I5384fc96c83c6f95ee19a04e8fc84211380f06a3