Add approval_required field License Compliance MR widget endpoing

Add field to indicate if approval is required to {project, namespace}-/merge_requests/{id}/license_scanning_reports_collapsed endpoint. Note: this endpoint isn't used yet in or MR widget, it's needed for the License Compliance MR widget migration to new components &7763 (closed)

Issue #356336 (closed)

How to test locally:

1. Create a project, and enable the License compliance feature
2. In Security&Compliance -> License compliance -> Policies disable one license (MIT for example)
3. Create MR where a component with MIT license is added to the codebase.
4. When license scanning is finished on MR, observe the response of GET {host}{project, namespace}-/merge_requests/{id}/license_scanning_reports_collapsed
5. Observe field approval_required added to the response.