Make the force stop dialog work properly in split screen

When it's in a multi-window mode, force stopping an app will lead to an
activity recreate, and the dialog fragment will also be recreated.
That's why the dialog still shows after the button is clicked.

Hence, dismiss the dialog before stopping the app to fix it.

Fixes: 231529730
Test: robotest
Change-Id: I75d27624f0c60bb617e7d1a92ffe01d3c0fbf7be

tests/robotests/src/com/android/settings/applications/appinfo/ButtonActionDialogFragmentTest.java

@@ -18,7 +18,9 @@ package com.android.settings.applications.appinfo;
 import static com.google.common.truth.Truth.assertThat;
 
 import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
@@ -72,6 +74,21 @@ public class ButtonActionDialogFragmentTest {
         verify(mTargetFragment).handleDialogClick(anyInt());
     }
 
+    @Test
+    public void testOnClick_forceStop_dismissDialog() {
+        ButtonActionDialogFragment fragment =
+                spy(ButtonActionDialogFragment.newInstance(FORCE_STOP_ID));
+        FragmentController.setupFragment(fragment, FragmentActivity.class, 0 /* containerViewId */,
+                null /* bundle */);
+        doReturn(mTargetFragment).when(fragment).getTargetFragment();
+        doNothing().when(mTargetFragment).handleDialogClick(anyInt());
+        final AlertDialog dialog = mock(AlertDialog.class);
+
+        fragment.onClick(dialog, 0);
+
+        verify(dialog).dismiss();
+    }
+
     @Test
     public void testOnCreateDialog_forceStopDialog() {
         ButtonActionDialogFragment fragment = ButtonActionDialogFragment.newInstance(FORCE_STOP_ID);