Export direct memberships - seat usage quotas page

What does this MR do and why?

This MR adds direct membership attributes to the exported CSV file in the seat usage quotas page.

Related issue: #389571

Screenshots or screen recordings

Before:

After:

How to set up and validate locally

1. Checkout the feature branch
2. Navigate to any group's usage quotas page(example: http://localhost:3000/groups/twitter/-/usage_quotas#seats-quota-tab)
3. Select the Export list option and review the downloaded csv file - includes direct membership information

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.