Expected Behavior

When SelectMultiple is being filtered by a search term a 'Select All' button should still appear.

Actual Behavior

The 'Select All' button is removed on search.

URL, screen shot, or Codepen exhibiting the issue

https://storybook.grommet.io/?path=/story/input-selectmultiple-default--default

Steps to Reproduce

1. Visit the story at the link above
2. Type something into search
3. 'Select All' button is removed

Your Environment

• Grommet version: v2.27.0
• Browser Name and version:
• Operating System and version (desktop or mobile):