Add feature specs where abuse_reports_list is enabled

This MR requires Support filtering abuse reports list by reporter (!114064 - merged)

What does this MR do and why?

This MR implements Add feature specs as part of https://gitlab.com/gitlab-org/modelops/anti-abuse/team-tasks/-/issues/157+.

It adds feature specs (abuse_reports_list FF enabled) to cover functionalities of the updated abuse reports list.

Screenshots or screen recordings

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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