Fix jump in animation for hotseat while re-arranging icons

While re-arranging icons the hotseat remains in scale 1.0f, while the workspace reduces it's scale (as defined by SpringLoadedState.java). Previously, the code to aggregate animations was assuming hotseat and workspace always had the same scale.

MultiScaleProperty.get() was being used to set the starting value of the animation. Previously, it was returning the last aggregated value. However, this value was correct only for the workspace, but not for the hotseat. Returning the current view scale makes it always correct.

Bug: 220271046
Test: Dragged icons from hotseat to workspace, and verified animation didn't jump
Change-Id: Ic01776c1d8e3967624626ed7c44d194a06295790