Make workspace and hotseat scale animations interruptible.

This affects app launches and returns to home. When launching
immediately after returning to home (before the return animation is
complete), the two animations could overlap, causing the two property
setters to conflict.

Bug: 367591368
Flag: com.android.launcher3.coordinate_workspace_scale
Test: tested with flag off and on, see before and after in the bug
Change-Id: Ie1483fa0bf589caee315ae298e9e68ca361709d8