Set the talkback focus to the header text when Stage is NeedToConfirm

Should set the talkback focus to the header text when the "Draw your
pattern again" page is shown.

Bug: 275728120
Test: 1. enable talk back
      2. Setup pattern lock
      3. In "Draw your pattern again" page, make sure the talkback focus
	 is set to the header view
Change-Id: If99a950488039840e8486ebb634f0070a9403916