Styling of Courses Catalog Visibility popup in Block Editor

### Reproduction Steps

1. Edit a course
2. Click on the link beside "Catalog & Search Visibility"

### Expected Behavior

Popup is readable and formatted nicely.

### Actual Behavior

Popup is compressed into a thin box

This issue has be recreated:
+ [ ] Locally
+ [ ] On a staging site
+ [ ] On a production website
+ [ ] With only LifterLMS and a default theme