Unexpected invisible button appears in Item Navigator and Host Navigator when navigating with the Tab key.

Preconditions:
Item Navigator or Host Navigator widgets must be created.

Steps to reproduce:
1. Open dashboard.
2. Use the Tab key to navigate through widgets in the UI.
3. Focus on the Item Navigator or Host Navigator widget.
4. Notice that an invisible button appears (visibly nothing changes, but focus is captured by an element).
5. Press Enter while this invisible button is focused.

Result:

No invisible or non-functional button should be focusable. Pressing Enter should not trigger any hidden buttons.

Expected:
This button should not be present at all.