Fail graph update if graph version didn't change

[eabatalov]

This provides a clear error message to customers showing them that they need to update graph version when deploying an update to it if they manually manage graph versions.

Testing:

make fmt
make test

Contribution Checklist

• If a Python package was changed, please run make fmt in the package directory.
• If the server was changed, please run make fmt in server/.
• Make sure all PR Checks are passing.