Fix themed settings icons.

- Added android prefix for homeAsUpIndicator attribute
- Override ic_arrow_down_24dp from androidx
- Remove ic_lock drawable overlay
- Update date and time icon
- Dedupe ic_menu_add and ic_add_24dp

Bug: 131346125
Test: mp settings;
Change-Id: I7223249f2adccc5569a37e8b68cae5499e7c7620

src/com/android/settings/biometrics/fingerprint/FingerprintSettings.java

@@ -396,7 +396,7 @@ public class FingerprintSettings extends SubSettings {
             Preference addPreference = new Preference(root.getContext());
             addPreference.setKey(KEY_FINGERPRINT_ADD);
             addPreference.setTitle(R.string.fingerprint_add_title);
-            addPreference.setIcon(R.drawable.ic_menu_add);
+            addPreference.setIcon(R.drawable.ic_add_24dp);
             root.addPreference(addPreference);
             addPreference.setOnPreferenceChangeListener(this);
             updateAddPreference();