[part 2] Update standalone picker to align widget loading and animations

In usual picker, widgets are already available before picker opens, so,
the work that happens during animations doesn't interrupt animations
on the scale it interrupt animations in standalone picker.

Bug: 346341156
Flag: EXEMPT bugfix
Test: Manual / see before after video
Change-Id: I7c8701447bd519b306799b28341d8f2f03daf59f