Send client relaunch event to WMCore.

By sending the local relaunch event to server side, WMCore can keep
the starting window when client remove the original window, and because
client won't preserve the original window, the result of redrawed view
will match the new configuration.

Bug: 230998394
Test: launch chrome => swipe to go home => change toggle to either light
or dark theme => launch chrome again. Verify the app won't become transparent and the starting window remains on screen until client
report finish draw.
Change-Id: Ic8f1ebaf0bbaf2b060338ca08a11069481c09b9a