Update the useSharedFacet typing

[viccon]

Typescript enforces invariance in generics which means that the useSharedFacet requires a single specific type. This leads to type errors when trying to pass a union, e.g:

const sharedFacet = getFacet(worldMode) // SharedFacet<CreateNewWorldFacet> | SharedFacet<WorldEditorFacet> | SharedFacet<RealmWorldEditorFacet>
const regularFacetUnion = useSharedFacet(sharedFacetUnion) // This errors because the types are not assignable to each other.

However, with the changes I'm introducing here the hook now leverages conditional types with infer to automatically distribute over unions. So when a union of shared facets is passed to useSharedFacet, the return type becomes a union of the corresponding facet types. Which means that the regularFacetUnion above will be of type Facet<CreateNewWorldFacet> | Facet<WorldEditorFacet> | Facet<RealmWorldEditorFacet>.

We are then able to use that facet union with our other hooks like useFacetMap:

const f = useFacetMap(
	(f) => {
		if ('worldData' in f) {
			return f.worldData
		}
		if ('realmWorldData' in f) {
			return f.realmWorldData
		}
	},
	[],
	[regularFacetUnion],
)

One downside is that the updated implementation now uses a type assertion (as InferFacet<T>) because typescript cannot automatically verify that the value returned by sharedFacet(driver) conforms to the conditional type. However, I believe that this cast is always safe based on the functions behaviour.