Defer gesture when IME is currently rendering nav buttons

Normally we only defer when touching the nav buttons themselves, but that will be difficult to propagate when IME is hosting the nav buttons. So just defer no matter what if IME is currently showing and rendering the nav buttons, ignoring the touch region.

Test: Enabled "persist.sys.ime.can_render_gestural_nav_buttons", ensure RecentsAnimationDeviceState#isImeRenderingNavButtons() returns true iff IME is showing in gesture nav.
Fixes: 215593010
Change-Id: I265cc042f9e24eb060f090febfbccebd3ba4d3c2