Misc fixes for settings

- Set device credential's Window flag to be SECURE. This prevents
  showing any pattern/pin in recent list.
- Disable tap sound on entity header

Fixes: 64339515
Fixes: 64413598
Test: visual
Test: runtest --path \
      tests/app/src/com/android/settings/password/ChooseLockGenericTest.java

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

@@ -68,7 +68,7 @@ public abstract class ConfirmDeviceCredentialBaseActivity extends SettingsActivi
             LinearLayout layout = (LinearLayout) findViewById(R.id.content_parent);
             layout.setFitsSystemWindows(false);
         }
-
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
         mIsKeyguardLocked = savedState == null
                 ? getSystemService(KeyguardManager.class).isKeyguardLocked()
                 : savedState.getBoolean(STATE_IS_KEYGUARD_LOCKED, false);