avoid calling convex functions directly (#33)

Avoid calling convex functions -- queries/mutations/actions/httpactions -- directly, as if they were js functions. Instead, their _handler property is the js function, if it exists.

This avoids a new console.warn which was added to "convex/server" which happens if you call a registered query/mutation/action/httpaction directly.

I added some types, but i'm not sure if this makes it actually safer. the main benefit was not needing casts to make the PublicHttpAction type flow through from router.lookup

Co-authored-by: Sarah Shader <[email protected]>

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Co-authored-by: Sarah Shader <[email protected]>