Don't end atomic animation when passing through state

Previously we were ending the atomic animation with the assumption
that it should be complete/almost complete by the time you drag to
the next state. However, it is very easy to drag quickly enough where
that assumption doesn't hold, and thus you just see the atomic
animation pop to the end (i.e. recents showing without animation).

Now instead of ending the atomic animation, we let it continue. But
because the new state animation will have an atomic component that
interferes with the still playing atomic animation, we have to
control the atomic component separately; we control the non-atomic
components until the atomic animation ends, at which point we create
a separate controller to control the atomic components.

Bug: 76449024
Change-Id: Ia4bf19e26d0838f952d9e500fbdd8aba19856a41