Fix cross task back window clipping with pinned taskbar

Bug: 315461656
Flag: Flag: ACONFIG com.android.systemui.predictive_back_system_animations STAGING
Test: Manual, i.e. visually verifying cross task back behaviour on Felix
Change-Id: I05a80b7b0a5766640d47ddb6b38150aa9aafd256
2 files changed