Avoiding MSDL haptics when first starting a drag in workspace.

The MSDL token to play haptics when dragging was being played as soon as
a widget was long-pressed but not dragged over a new drop-off location.
Haptics should only play while the UI item is being hovered over new
cells. The new condition checks if the drag cell and drag cell span are
cleared and avoids playing haptics in this initial state.

Test: manual. Verified haptics while dragging icons over Workspace and
  Hotseat only when actually dragging over new cells.
Test: manual. Verified haptics with adb shell dumpsys of Launcher and
  checking the MSDL token history.
Flag: com.android.launcher3.msdl_feedback
Bug: 376103470
Change-Id: I7b2056f1c713b65f9df37f3138c1acf3b5376822