🐞 Changing "Use Theme Background" does not apply to gutter

### Description

When disabling the "Use Theme Background" option, the gutter still uses the theme background rather than the standard background.

### To Reproduce

1. Enable a theme and use the theme background.
2. Observe the colour of the theme background.
3. Disable the "Use Theme Background" option.
4. Observe the colour of the gutter

### Expected Behavior

The gutter should also use the standard background as opposed to the theme background.

### Version Information

CodeEdit: 0.0.3-alpha (36)
macOS: 13.5

### Screenshots