Filter to Only Active Memberships in Members::DestroyedWorker

What does this MR do and why?

Filter to only active memberships in Members::DestroyedWorker.

Ignore pending memberships. Ignore invitations and requests. This brings worker behavior in line with billable member queries.

Issue: https://gitlab.com/gitlab-org/gitlab/-/issues/552138+

References

• We originally made this worker count blocked memberships in Only remove SeatAssignment if no other membership (!173699 - merged).
• With a reference in that MR to the conversation here explaining why: !169756 (comment 2226248060)
• Query performance of the change introduced in this MR is here: https://gitlab.com/gitlab-org/gitlab/-/issues/552138#note_2597215848

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