Still hard to see scroll bar

### Bug description

Why can't you fill in the scroll bar with a light color so we can see it more easily?

### Steps to reproduce

use audacity to record anything

### Expected behavior

should be easy to see the scroll bar. People with cataract replacements need a lot of contrast.

### Actual behavior

a hard to see scroll bar

### Audacity Version

Audacity 4.0.0

### Operating system

macOS

### Additional context

_No response_