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: atest android.view.textclassifier.TextClassificationManagerTest \
            android.text.util.cts.LinkifyTest \
	    android.text.util.LinkifyTest \
	    android.widget.TextViewActivityTest

Change-Id: I01b5e936aa4dfc937a98f50e9fc8171666861a61
(cherry picked from commit a69950ce)