Do not boost the dimmer if the adjacent TF is dimming

When showing two activities side-by-side with AE, it is possible
to have both two activities showing dialogs with dim. The dimmer
surface in the primary container should not be boost in that case.

Bug: 323083755
Test: steps on the bug
Change-Id: Ib625e8bde16e4f9729794d0dad99c82dce44f282