Fix occasional crash in VirtualDeviceManagerService

If a VirtualDevice is closed very soon after an Activity is displayed
on one of its VirtualDisplays, we can get a crash in
VirtualDeviceManagerService because a late call to
notifyRunningAppsChanged just after the close both leaves
mVirtualDevices and mAppsOnVirtualDevices out of sync about whether
the device still exists, and also dispatches the
onAppsOnVirtualDeviceChanged to listeners via the LocalService where
listeners may try and get the device that's already been removed.

This problem happens occasionally when running CTS tests where we are
often tearing down a VirtualDevice at the end of a test just after
starting an Activity and verifying something, but is likely rare in
regular device usage.

Bug: 265825399
Test: atest VirtualDeviceManagerServiceTest
Change-Id: I11f3d85a9ed81a57cebd561bd0ba3c28d75f520b