ui: Fix `end_slot_on_hover` API (#59805)

The issue here was that `end_slot_on_hover` would currently only work if
`end_slot` was also set. With this, it will now work even if there is no
`end_slot`.

Release Notes:

- N/A
d655580d9bFinn Evers committed on 6/24/2026, 9:11:41 AM· committed by GitHubparentaa7dc30
1 file changedLine totals unavailable