Fix missing transition with visibility change when changing opaque

This aligns OPEN scene transition with CLOSE scene transition that
consists of 2 transitions:

OPEN = OPEN (startActivity) + TO_BACK (convertFromTranslucent)
CLOSE = TO_FRONT (converToTranslucent) + CLOSE (finish)

The TO_BACK was missing. That causes the visibility change to be
committed immediately with surface placement, which increases the
execution time of convertFromTranslucent.

Also removes requestTraversal because setOpaqueLocked will call
scheduleAnimation that is enough to update surface attributes.

Bug: 314261955
Test: UiBenchActivityTransitionsAnimationMicrobenchmark
Change-Id: I4c5e401c6f7fd53650ac49b527df98bc00b8534a