(1/n) Disabling OHM gesture in NavigationBar 3 Button mode

1) UX mentioned the swipe gesture in 3-Button NavgationBar area
may confuse user from taping NavBar buttons(Back, Home, Recents).
They decide to disable the swipe gesture and allow user to trigger
One Handed Mode(3 Button Mode) through A11y shortcut.
However, user can still use OHM by enabled shortcut button on
both Gesture Navigation & 3-Button mode.

2) OHM gestural handler consume the touch event while window
Magnification overlap with NavigationBar area in 3-button mode,
this result Magnification function can no long obtain the control.

Bug: 184903678
Bug: 179648683

Test: manual
Test: atest WMShellUnitTests
Change-Id: Ib9a06e19d749707e6f5e08c3ef803c1681f86bbc