Make bouncer title not selectable in talkback

The title should announce the text but should not be selectable in a11y
services.

Test: Open bouncer with talkback on.
Fixes: 260986759
Change-Id: Iaf2291754cbbfec859360721db6982ec7fcb3dff
Merged-In: Iaf2291754cbbfec859360721db6982ec7fcb3dff
(cherry picked from commit 30e756d3)