Fixes talkback accessibility on learn more link.

Uses the LinkTextView, which handles partial url talkback
in textviews for accessibility. Also cleans up some string
spacing and changed an instance of Tap & hold to
Touch and hold for clarity.

bug:27171497
bug:26562712
Change-Id: I059a782a952ac962537c374959ee740962d6016f
4 files changed