Mark TaskbarOverlayProxyView closed sooner

Marks TaskbarOverlayProxyView closed earlier in handleClose, before
removing it as a view from the drag layer. BaseDragLayer expects that a
floating view is closed by the time it gets removed, and asynchronously
issues another close call if this is not the case as a workaround.

Marking the proxy view closed sooner also reduces chances of reentrant
close call while handling current close.

Bug: 368119679
Test: Opening/closing all apps, folders, KQS
Flag: com.android.launcher3.taskbar_overflow

Change-Id: I33ccb82ebd7e967f2e47f38db3e41527dad9d573