extensions always claim languages #13859
Description
While analyzing the ExecutionEngineDiscovery.claimsLanguages() protocol, I noticed that extensions will always claim their language, because they are considered as user engine preferences and go to the top of the list.
This means that the julia engine is currently "stealing" julia from the jupyter engine, and the marimo extension will grab python from jupyter as well.
So... it seems there is no way around it; we are forced to improve the claimsLanguage protocol. 🤣