saved_desks: Chromevox announce on restore

Make chromevox announce the current name of the desk instead of the desk
position number when restoring from a saved desk or changing the name of
the default desk in the zero state.

Bug: 1349846
Test: manual
Change-Id: I88d951d10106dfbab27387777156c15089441d61
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3817243
Reviewed-by: Daniel Andersson <dandersson@chromium.org>
Commit-Queue: Andrew Pantera <andp@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1033769}