Reset bottom clip instead of setting ime top to 0

Setting proper bottom clip value on bubble bar expanded view after
collapse animation is completed.

Fixes: 416297086
Flag: com.android.wm.shell.enable_create_any_bubble
Test: Manual.
Create any bubble. Expand and collapse it. Expand again. Rotate device
and repeat expand/collapse check. Fold/unfold repeat expand/collapse
check.
Create any bubble that will have an input inside the task
view. Click on it to show keyboard. Rotate the device couple of times.
Task is clipped correctly for every rotation.
Used the device mentioned in the bug.

Change-Id: I0c4bd980c9627f4e200836b4d9c81165b2f53d09