Remove "Add seats" btn from usage quotas for community plans

What does this MR do and why?

Solves #415055 (closed)

Needs https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/8274

Screenshots or screen recordings

group w/out community programs	group w/ community program

How to set up and validate locally

1. Navigate to http://localhost:3000/ and create a new group
2. Create a subscription with any community programs and link namespace to group created above
3. Navigate to http://localhost:3000/groups/<name-of-group>/-/usage_quotas#seats-quota-tab and confirm the the Add seats button is not visible.
4. Navigate to any other group without community programs and confirm that the Add seats is visible

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.

Related to #415055 (closed)