[VSA] API extension for applying filters to the chart of "Type of Work"

Problem to solve

The API endpoints for the Type of work chart doesn't support Milestone, Author and Assignees.

Related to #258680 (closed)+

Proposal

backend work to apply all the filters from the filter bar to the Type of work chart.

1. Labels - already supported by the API endpoint, but not on the Type of work chart.
2. Milestone
3. Author
4. Assignees

*date_range filter already applies to type of work.