Fix accessiblity issue around work tab

1. Instead of always announcing "Apps list", we now announce
"personal apps list" and "work apps list" if tab is there.
2. Fix an issue that "personal" and "work" are announced twice.
3. Work footer is now announced as a group

FIX: 71703082

Change-Id: I0240bc04df09a5599540cfe67f0f48156f285548