Only create Prisma v5/v6 db spans when there is a parent span #25802

The Prisma v5/v6 tracing helper creates db spans when there is no active span. Each of these spans becomes its own root span and has no context. The orchestrion path already requires a parent.

In packages/server-utils/src/integrations/prisma/tracing-helper.ts, create no client span when there is no active span.

Add a test that checks that an operation without an active span creates no span.