Fix deferred shortcut container removal.

- Previously, the drag listener listener was removed from the
  container as soon as it started animating closed, which got
  rid of its opportunity to complete the deferred removal.
- The deferred removal now calls close(), which does further
  cleanup including updating the app icon's text visibility.

Bug: 31248681
Change-Id: I18e545e7e19e50b7d47e23a5beb8f254ba1a4ccf