Clear the previous CompatDisplayInsets when new activity is launched

When a new activity is launched from Task letterbox activity, it will
first use the existing Task bounds, so we need to make sure the size
compat for that bounds is cleared when it requests orientation.

Bug: 170725334
Bug: 155431879
Test: atest WmTests:SizeCompatTests
Test: manual: adb shell wm set-ignore-orientation-request true
Change-Id: I86a206be030c3c250fb40590e7515e75620eaaf7