Don't apply alpha to statusbar during unfold anim on launcher

The alpha changes to statusbar were introduced to to hide it during the unfold animation while on apps, as the ounds of the app "collapse" to the center, but the statusbar doesn't.
While on launcher, this alpha is not needed.

Bug: 271413648
Test: StatusBarMoveFromCenterAnimationControllerTest + manual
Change-Id: I01389402515582038f872957ee6f9049a00100d7