Add FLAG_SECURE for ChooseLockPassword and Pattern

Prevent ChooseLockPassword and ChooseLockPatten being projected to
remote views, add FLAG_SECURE for these screens.

Bug: 179725730
Test: Check these 2 screens not projected to chromecast
Test: robo test for SetupChooseLockPatternTest ChooseLockPatternTest
      SetupChooseLockPasswordTest ChooseLockPasswordTest
Change-Id: I7449a24427c966c1aa4280a7b7e7e70b60997cca

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

@@ -41,6 +41,7 @@ import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.WindowManager;
 import android.widget.TextView;
 
 import androidx.fragment.app.Fragment;
@@ -175,6 +176,7 @@ public class ChooseLockPattern extends SettingsActivity {
         ThemeHelper.trySetDynamicColor(this);
         super.onCreate(savedInstanceState);
         findViewById(R.id.content_parent).setFitsSystemWindows(false);
+        getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
     }
 
     @Override