Orphaned team created in database despite HTTP 500 response

[Kapsik89]

Steps to reproduce:

1. Follow steps from Bug— remove tester7 from a team, then have tester7 attempt to create "Team Seven"
2. Observe the HTTP 500 response on POST /api/teams/portal/create-team
3. Navigate to Browse Teams

Expected behavior:
If the team creation fails with HTTP 500, no team record should be written to the database. The operation should be fully atomic — either it succeeds completely or rolls back entirely.

Actual behavior:

• Despite the HTTP 500 response, "Team Seven" appears in Browse Teams
• The team has 0 members — tester7 is not assigned as owner or member
• Tester7 has no access to the team and cannot manage or delete it
• An orphaned, ownerless team record exists in the database