Update taskbar drag and drop treatment

- Disable the FastBitmapDrawable icon instead of setting it to invisible
- Suspend auto hide during drag and drop (moved to new TaskbarAutoHideSuspendController)

Test: Drag and drop from taskbar and ensure the original icon stays in place but desaturated
Test: Open immersive app, drag and drop from taskbar and ensure taskbar doesn't hide before drop
Fixes: 200816442
Change-Id: I4b895efd043be75e7e7034bd75e751ffdd2cfdd7