Accessibility: ng-select ARIA roles and controls (combobox, listbox, option) improperly set

Describe the bug The following aria roles on the searchable multi-select dropdown are improperly set: combobox, listbox, and option. Aria-controls is also not set on the text input element.

To Reproduce Steps to reproduce the behavior (if example is not provided):

1. Render the ng-select component, as long as some options are populated, there’s nothing special that needs to happen. The following properties were used to configure the component

<ng-select [items]="options"
      [bindLabel]="labelProp"
      [multiple]=true
      placeholder={{placeholder}}
      [formControl] ="formControl"
      labelForId={{id}}
      aria-label="multiselect-dropdown-widget"
      class="custom"
      >

1. The accessibility assessment was done using the FastPass feature which comes with the ‘Microsoft Accessibility Insights for Web’ extension, available on chrome and edge.
2. Once the fastpass is run, the aria-required-children check will fail. There are two cases where this fails, which demonstrates the incorrect configuration of aria roles. See screenshots below.

Expected behavior Based on WCAG 1.3.1 standards, the input text box should be contained in a div with role="combobox", and the options should be contained in a div with role="listbox". Furthermore, the input text box should have an attribute aria-controls which is linked to the listbox id, similar to how aria-owns property is already used. Currently, the entire ng-select component has the role="listbox" while the input element itself has role="combobox".

This links gives an overview of the rule in question https://dequeuniversity.com/rules/axe/3.5/aria-required-children?application=msftAI

This links provides a good example of the correct way to set these roles https://www.w3.org/TR/wai-aria-1.1/#combobox

Screenshots This is the check which fails when the dropdown is not open:

This is the check which fails when the dropdown is opened:

Desktop (please complete the following information):

• OS: Windows
• Browser: Edge (chromium)
• Version: 3.5.0

[isaacfimbres1]

I already have an approval on this PR https://github.com/ng-select/ng-select/pull/1673, just need someone with write access to approve!

[AElmoznino]

Any updates on this? I would love to have 100 a11y score when using ng-select 😄