The transformhelper now also transforms gone views

Because a notification's views could change from GONE
to VISIBLE without notifying the transformhelper, we're
now adding the transformed views even if they are gone
at the resolution time.
This fixes a bug where the Time would fade in / out
properly.

This also fixes another bug where the time could remain
invisible.

Test: add notification group without any header text and observe smooth fading when expanding group
Change-Id: I1d6b0126df1550a71baa2e7729bdf9664b934b02
Fixes: 35127160