Group filteredsearch tokens from URL params

What does this MR do and why?

Continue from Basic group multiselect support for user token (!133725 - merged) for #395713 (closed)

On issue list page, for author and assignee, group URL params together in filter bar for OR and NOT filtered searches.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. In rails console enable the feature flag

   Feature.enable(:group_multi_select_tokens)

2. Example URL: http://gdk.test:3000/gitlab-org/gitlab-test/-/issues/?sort=created_date&state=opened&or%5Bauthor_username%5D=root&or%5Bauthor_username%5D=vickie_conn&first_page_size=20
3. Add some assignees or authors using OR and NOT filters, and submit the filter.

MR acceptance checklist

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