Hook one-handed gesture to expand notification panel by default

Notify to expand notification panel through SystemUiProxy when
one-handed mode disabled and one-handed gesture detected.

Bug: 154080211
Test: make and install
Test: manual disable one handed mode and swipe down to trigger
Test: verified the gesture works even outside of home page
Change-Id: Iacc0e506ccd04dd81f6182759c8af7d686a7b77b