Issues atom feed url reflect filters on dashboard

Makes the issue atom feed url reflect the selected filters on the issue dashboard page and project's issues page.

## Are there points in the code the reviewer needs to double check?

The solution isn't based on javascript and filters functionality but on the current url parameters. It didn't seem right especially when writing tests.

## Why was this MR needed?

After filtering the issues, users may press the feed button and see a different list of issues to what is shown on the HTML page

Closes #22947

See merge request !7259