feat(organizations): show subscription plan in organization view TASK-1605

[Guitlle]

🗒️ Checklist

1. run linter locally
2. update all related docs (API, README, inline, etc.), if any
3. draft PR with a title <type>(<scope>)<!>: <title> TASK-1234
4. tag PR: at least frontend or backend unless it's global
5. fill in the template below and delete template comments
6. review thyself: read the diff and repro the preview as written
7. open PR & confirm that CI passes
8. request reviewers, if needed
9. delete this section before merging

📣 Summary

Show the organization subscription plan summary in the organizations admin edit view.

👀 Preview steps

1. Enable stripe (see in Notion how to set it up)
2. Get a user
3. Make a paid plan purchase
4. Go to the django admin, Organizations, and select the organization from the user you used for the test
5. Check that the Subscription Plan read only field has the correct information

[noliveleger]

LGTM, works as expected.