Open issues page: Missing grouping of radio buttons under Switch filter button

Steps to reproduce:

1. Navigate to and activate "Projects" link from the banner region and select any project.
2. Navigate to and activate the "Issues" link from the left navigation menu.
3. Navigate to and activate the "Switch filter" menu button.
4. With screen reader running in background, activate down arrow keys and observe the announcement.

Actual behaviour:

When screen reader users use JAWS/ NVDA to navigate the page, the role of "radio" is not announced for all the radio buttons present under "Switch filter" menu button. Moreover the parent <ul> used to group all radio buttons is missing role of "radiogroup" which created confusion for screen reader users as it was difficult to predict that the radio buttons belonged to same group and what is the total count of radio buttons present.

In addition, the "checked" status of radio button is not announced to screen reader users.

Expected result:

1. The role of "radio" should be announced for each radio button along with its position in the radio group. For eg: "Open issues radio button 1 of 5"
2. The checked state of radio button should be announced to screen reader users.
3. As soon as the popup open the focus should be set to the first radio button i.e "My open issues".

Code example:

<button id="subnav-trigger" role="button" aria-label="Switch filter" 
aria-haspopup="true" aria-controls="subnav-opts" aria-expanded="true">Switch filter
</button>
<ul id="subnav-opts" role="radiogroup" aria-labelledby="subnav-trigger">
<li role="none">
<a aria-checked="false" tabindex="0" role="radio">My open issues</a>
</li>
<li role="none">
<a aria-checked="false" tabindex="-1" role="radio">Reported by me</a>
</li>
<li role="none">
<a aria-checked="true" tabindex="-1" role="radio">Open issues</a>
</li>
</ul>

AXQA Ref:AXQA-114