Finish ClockFacePickerActivity on "Apply" click.

Fixes: 133651908
Test: maunal - picked new clock and placed phone on stand.
Change-Id: Ib734fac0646656d87f179615cd16c969b48bcc5f
diff --git a/src/com/android/customization/picker/ClockFacePickerActivity.java b/src/com/android/customization/picker/ClockFacePickerActivity.java
index 261f794..bfe2e5e 100644
--- a/src/com/android/customization/picker/ClockFacePickerActivity.java
+++ b/src/com/android/customization/picker/ClockFacePickerActivity.java
@@ -56,6 +56,7 @@
                 result.putExtra(EXTRA_CLOCK_FACE_NAME, option.getId());
                 setResult(RESULT_OK, result);
                 callback.onSuccess();
+                finish();
             }
 
             @Override