Search - Advanced Search : Combobox is missing appropriate roles and/or attributes

Issue Summary

On "Search" page(that becomes available when user activates "Advance Search" link) the elements such as "CONTRIBUTOR" and "IN SPACE" functions like a combo-box but are missing required ARIA roles and attributes

Steps to Reproduce

1. Navigate to "Search" input field and activate it.
2. Navigate to "Advance Search" link and activate it.
3. Navigate to "CONTRIBUTOR" and "IN SPACE"  elements. 

Actual Behaviour

The elements such as "CONTRIBUTOR" and "IN SPACE" functions like a combo-box but are missing required ARIA roles and attributes due to which screen reader users not able to interact with it effectively.

Expected Behaviour

The elements "CONTRIBUTOR" and "IN SPACE" 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: 719700