(aria-required-children): does not allow separator in listbox

### Product

axe-core

### Product Version

_No response_

### Latest Version

- [X] I have tested the issue with the latest version of the product

### Issue Description

#### Expectation
Accessibility tests to pass.

An item with role=separator should be acceptable as a child of an element with role=listbox.

#### Actual
Accessibility test fails aria-required-children test.

Error:

Fix any of the following:

Element has children which are not allowed (see related nodes)
Element has no aria-busy="true" attribute

Related node:

li[role="separator"]

#### How to Reproduce
html sample:

```html

• 
  Home
  




• 
  Colors
  

```