vendor openapi-telemetry in `validate-v2`

1. We want to get rid of the package and repo [openapi-telemetry](https://dev.azure.com/devdiv/DevDiv/_git/openapi-telemetry)
2. The only remaining usage is in the `validate-v2` image
3. The validate-v2 image uses _only_ this package to emit Geneva telemetry

Given that our team originated the decision to maintain this package, I'm going to take the item vendor it into validate-v2. Any further CG issues or follow-up will be owned by the RPaaS team.