This PR adds hover colors to the editor scrollbars:


https://github.com/user-attachments/assets/6600810e-7e8e-4dee-9bef-b7be303b5fe0

The color used here is the existing `scrollbar_thumb_hover_background`
color provided by themes.

Looking forward to feedback 😄 

Release Notes:

- Added hover state to editor scrollbars.