Cosmos DB Emulator Gremlin support does not work following instructions

We currently have plans for a big migration to Gremlin using CosmosDB. But we've fallen short at the first hurdle, my colleague and I have both gone through the [instructions to use the Gremlin API](https://learn.microsoft.com/en-us/azure/cosmos-db/local-emulator?tabs=ssl-netstd21) and have both fallen short.

Essentially after running through the documentation we're left in the same situation as we were before; a Cosmos DB emulator without an option to switch to the Gremlin API:

Are we missing something here or has a bug been introduced?

Start by following the linked Cosmos DB Emulator instructions and reproduce the missing Gremlin API option. The issue names no repository files or tests; done means determining whether the emulator behavior is a bug or the instructions omit a required step, then documenting the confirmed finding.

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