Edit a Page - Restrictions Modal : Combobox is missing appropriate roles and/or attributes

Issue Summary

 On "Restrictions" modal dialog, the element "Can Edit" is functioning like a combo-box but is missing ARIA roles/attributes.

Steps to Reproduce

1. Navigate to "Spaces" button present in header region and activate it
2. Navigate to any "Space link" from the list of links which becomes available when user activates "Spaces" button.
3. Navigate to "More options" link present in main content area and activate it.
4. Navigate to "Restrictions" link and activate it.

Actual Behaviour

The elements such as "Can Edit" is functioning like a combo-box but is missing required ARIA roles and attributes due to which screen reader users not able to interact with it effectively.

Expected Behaviour

The element "Can Edit" should be coded with role="combobox" appropriately with attributes such as aria-haspopup="listbox", role="option" provided for combo-box items etc.

For more details on accessible combo-box please refer this link -> https://www.w3.org/TR/wai-aria-practices-1.1/examples/combobox/aria1.1pattern/listbox-combo.html 

Screenshot

Workaround

workaround

Bug Ref: 725269