desktop-exploded-view: Explode desktops when swiping up from home

This change makes it so that the explode animation only happens when
swiping up from the desk. In other cases, the desk is immediately set
to its exploded state.

The desk explode progress is now exposed as a FloatProperty in
RecentsViewUtils.

Flag: com.android.launcher3.enable_desktop_exploded_view
Test: Manual
Bug: 367353392
Change-Id: I5adec7db1fdc933860dce7fcca0a47cec0672ee7