Reapply "Unify registration and NM assignment in NAI"

Now that faulty Telephony tests have been disabled temporarily
to allow for this bugfix, this can be reverted.
This reverts commit 30fcf820f92470a824d2a083907e03a609ecaf35.

Test: FrameworksTelephonyTests CtsNetTestCases
Change-Id: I57f25f5e6481106255df0ab69558e351eb938f68
2 files changed