Add existing actions to the new abuse reports list

Resolves https://gitlab.com/gitlab-org/modelops/anti-abuse/team-tasks/-/work_items/286?iid_path=true

What does this MR do and why?

Add actions that admins can take in the current abuse reports list implementation¹ to the new implementation (behind abuse_reports_list FF). This allows us to enable abuse_reports_list without waiting for the completion of add bulk actions to abuse reports list and abuse reports details view (contains actions for the report).

¹

Screenshots or screen recordings

Action	Existing	New
Block user	Screen_Recording_2023-03-20_at_10.22.01_AM	Screen_Recording_2023-03-20_at_10.23.31_AM
Remove report	Screen_Recording_2023-03-20_at_10.29.28_AM	Screen_Recording_2023-03-20_at_10.27.35_AM
Remove user & report	Screen_Recording_2023-03-20_at_10.34.44_AM	Screen_Recording_2023-03-20_at_10.37.43_AM

How to set up and validate locally

1. Enable the feature flag

   $ rails console
   > Feature.enable(:abuse_reports_list)

2. Login with an admin account

3. Go to the Abuse Reports page (http://localhost:3000/admin/abuse_reports)

4. Validate that each report row has its own actions dropdown

5. Validate that each action works as it does in the existing abuse reports list (see demo videos above)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.