Improve performance of `createTransactionForOtelSpan`

### Description

![Image](https://github.com/user-attachments/assets/f21e3a05-6a04-41ee-b1d6-6d7e70f801c2)

https://github.com/getsentry/sentry-javascript/blob/ef2f35d5863ce5e581a36aac9ce4557a9ebe370c/packages/opentelemetry/src/spanExporter.ts#L235