perform accessbility focus when the recyclerview doesn't gain focus

after fragment replacement in SettingsActivity

Bug: 145475911
Test: Settings -> App & Notifications -> Default Apps -> Enable Talkback
-> Gear Button next to Home app -> About -> Verify Talkback reads the
first item in the page

Change-Id: I100e646ad2aba0081b48b86ec408ce8e76a80713