Unhide and rename PhoneNumberUtils tts methods

Renamed ttsSpanAsPhoneNumber #1 -> getPhoneTtsSpan
Renamed ttsSpanAsPhoneNumber #2 -> addPhoneTtsSpan

Instead of removing the original hidden methods, I deprecated them.
Since Telephony changes initially get checked into wireless-dev
branch and dialer/contacts changes get checked into master branch,
immediately deleting the ttsSpanAsPhoneNumber methods would break
builds.

In ContactsCommon, I plan on removing
ContactDisplayUtils#getTelephoneTtsSpannable and instead using
these Telephony APIs. Numbers I tested worked in ToT master talkback:
911, (650) 215 3111, 22222222222, 333-3333, 013334612234, +1 905 471 8484,
001 39 02 444 4444. The changes in this diff cause the numbers
to be talked-back at least as well as before.

Some context: go/question-about-telephonys-ttsspan

Bug: 18777272
Change-Id: I3a6ead3ee9c030761bde903cf88f4aa4fc7a3460