SF: Do not abort on duplicate hotplug disconnect

processHotplug expects the display token to exist for disconnect events,
so skip events that disconnect an already disconnected display.

Bug: 241286153
Test: HotplugTest.ignoresDuplicateDisconnection
Change-Id: I2b711317acc87f453f73a1aafcc8dd63cc1a8d33
2 files changed