Through a transaction-mode pooler Prisma takes pg_advisory_lock(72707369) on one
backend and releases it on another, so the first backend keeps the lock while idle
and the next boot waits on it. Migrations now run with
PRISMA_SCHEMA_DISABLE_ADVISORY_LOCK=1 while LiteLLM holds the coordinator lock and
Prisma's key as transaction-level locks on one pinned connection, so nothing can
outlive the migration
Resolves LIT-9571
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>