chore: clean-up buf workspace

[julienrbrt]

Description

orm/internal contains no protobuf files and isn't used.
We do not need that in our buf.work.yaml.
Additionally, this poses problems if you are doing a buf export from outside the repository.

Eventually, it will be useful to add all proto workspaces if and after this gets merged (#18758, writing this as remember for myself, no actionable here)

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