pin @node/types to 20.8.3

[jrhender]

I noticed that stampy.ts tests are failing (e.g. https://github.com/StampyAI/stampy-ui/actions/runs/7854687158/job/21435971107) with the following error:

    app/server-utils/stampy.ts:196:45 - error TS2576: Property 'json' does not exist on type 'Response'. Did you mean to access the static member 'Response.json' instead?

    196     json = await (await fetch(url, params)).json()

I think it is due to the types conflict described here.

This PR removes @types/node to remove the conflict. This doesn't seem to break the app or any tests.

[Aprillion]

IMHO it was probably due to stale node_modules - happened to me a few times and deleting them and reinstalling helped for me, so I guess any change in package.json "fixed" it for you :D