RESTRICT AUTOMERGE Do not linkify text with RLO/LRO characters.

Also don't show smart actions for selections in text with unsupported
characters.

Bug: 116321860
Test: runtest -x cts/tests/tests/text/src/android/text/util/cts/LinkifyTest.java
Change-Id: Ib2ee544b5783234fba8ee2f93adf0b36b039520f
(cherry picked from commit 4e3507d5)