Remove creator_id

[cocomarine]

Status

• Closes https://github.com/RaspberryPiFoundation/digital-editor-issues/issues/1841

What's changed?

• Removed the creator_id column from the School model
• School creation no longer takes a creator. The controller passes current_user.id as owner_id to School::Create, which passes it to SchoolOnboardingService#onboard to create the owner and teacher roles
• School::Create takes a Postgres advisory transaction lock keyed on owner_id before saving the school
  • This serialises concurrent creations by the same owner.
  • Previously the creator_id uniqueness constraint prevented duplicates.
• School::Create runs in a savepoint (requires_new: true), so a failure rolls back the school even when called inside an outer transaction (e.g. SchoolImportJob)
• Role validation failures during onboarding, for example when the user already has a role in a different school, are merged into the school's errors and returned as a failed response. They are not sent to Sentry. Other RecordInvalid errors are sent to Sentry
• Removed creator_id from the admin dashboard
• Updated the seeding rake tasks
• Moved the UX contact consent sync from ContactSyncJob to RoleSyncJob for the owner role
  • With ownership transfer, this means the new owner's Salesforce Contact will be marked as opted in without that person's consent
  • New issue written for allowing owners to opt in/out: https://github.com/RaspberryPiFoundation/digital-editor-issues/issues/1860

[github-actions]

Test coverage

93.84% line coverage reported by SimpleCov.
Run: https://github.com/RaspberryPiFoundation/editor-api/actions/runs/37485866504