Fix the flaky screenshot test

The flake happened to be due to rebinding triggered on attachToWindow that reset the icon cache with placeholder icon

Based on what I see, instead of calling refresh and bind, just triggerring onWidgetsBound should be okay - assuming it was trying to bind view for case when theme or display size was changed while picker was open.

Bug: 337916664
Change-Id: Ic6f3ff9188e4c5eda141a948ffa0c2c7c685162e
Test: Screenshot test
Flag: EXEMPT bugfix for test