[a11y] Fix Switch Access keyboard input issue in AA+.

See https://buganizer.corp.google.com/issues/308704236#comment7. The issue is only reproducible when "Swipe up to start search" is OFF.

Video: https://drive.google.com/file/d/14ONBHL-qK3xaDWVruSMdQXWRGisyBSc2/view?usp=sharing

Bug: 308704236
Flag: NA
Test: manual
Change-Id: If84c1fcdb65add658022520018e34ad958be6bc2