Accessibility of clear-all button

Making it visible to accessibility even when it’s completely hidden
behind a task. I had to mark it visible as a view. Now it’s invisible
only when there are no tasks in RecensView, to hide it from
accessibility.

Focusing on the button completely reveals it.

Bug: 72222505
Test: Manual
Change-Id: Ia31a1136e07faed93b4a44d5be69483d3b88364d