Initialize SplitSelectStateController for 3P before setting content view

* RecentsView#onAttachedToWindow relies on splitSelectStateController
being initialized, so we now do it before RecentsActivity calls
setContentView()

Bug: 332643607
Test: Couldn't repro before or after :(
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:4276ee4897f59cfb1a2e432adfe54196b1a0dd2d)
Merged-In: Ic26460e08ca74adcf6dcf31abc956ad57f4061c2
Change-Id: Ic26460e08ca74adcf6dcf31abc956ad57f4061c2