Preserve qsFullScreen update in NSSL

This was removed initially with the FooterViewRefactor, but we should
keep it in case it could cause any issues. I was hoping it would fix
b/329432313 but unfortunately it doesn't.

Bug: 293167744
Test: existing tests should pass
Flag: ACONFIG com.android.systemui.notifications_footer_view_refactor STAGING
Change-Id: Ia6a3506f05b8d45b35c3ef2160c9d34c96dbfdb5