Fix TalkBack announces disruptive announcement in PIN/PWD page.

Set the description state to A11y Node info for
"Must be at least 4 characters" when enter "Set a password",
"Must be fewer than 17 digits" in the "Set a PIN" or "Set a password"
and "PIN must be at least 4 digit, but a 6-digit PIN is recommended
for adding security"

Flag: EXEMPT bugfix

Bug: 384588020
Bug: 384604918
Bug: 384619356

Test: local build and verify Talkback announcement in PIN/PWD page.
Change-Id: Ib81abdc41dba1eeb854f2c7361362b5d55f8c7c7

src/com/android/settings/password/ChooseLockPassword.java

@@ -560,6 +560,7 @@ public class ChooseLockPassword extends SettingsActivity {
             setupPasswordRequirementsView(headerLayout);
 
             mPasswordRestrictionView.setLayoutManager(new LinearLayoutManager(getActivity()));
+            mPasswordRestrictionView.setAccessibilityLiveRegion(ACCESSIBILITY_LIVE_REGION_POLITE);
             mPasswordEntry = view.findViewById(R.id.password_entry);
             mPasswordEntry.setOnEditorActionListener(this);
             mPasswordEntry.addTextChangedListener(this);