Ensure SysUI gets VIS callback when session's over

There are chances that SysUI does not get the
onVoiceSessionWindowVisibilityChanged(false) callback if the
voice interaction window was visible then the connection is closed.

This could cause issue for TaskBar since TaskBar relies on the callback
to clear its intermediate state.

Video: http://recall/-/b1EZhgUkQcpML5OwZekLBN/giEfwSaYA9saSOfGQwCAus
Bug: 254070601
Test: follow the reproduce steps in bug, see also video
Change-Id: I0222eea38179620c36253f47f332536ffb9e434c