Remove extraneous types in graphql schemas

[mattjohnsonpint]

Replaces #236, which was reverted in #241

Fixes HYP-1388

[linear]

HYP-1388 Runtime generates extraneous types in the GraphQL schema

Consider the example project at https://github.com/hypermodeAI/functions-as/tree/main/examples/http

The generated GraphQL schema from the Runtime is:

type Query {
  createGithubIssue(owner: String!, repo: String!, title: String!, body: String!): Issue!
  getExampleHtml: String!
  getRandomImage(width: Int!, height: Int!): Image!
  getRandomQuote: Quote!
}

type Header {
  name: String!
  values: [String!]!
}

type Headers {
  data: [StringHeaderPair!]!
}

type Image {
  contentType: String!
  data: String!
}

type Issue {
  title: String!
  body: String!
  url: String
}

type Quote {
  quote: String!
  author: String!
}

type Request {
  url: String!
  method: String!
  headers: Headers!
  body: String!
}

type Response {
  status: Int!
  statusText: String!
  headers: Headers!
  body: String!
}

type StringHeaderPair {
  key: String!
  value: Header!
}

It should be:

type Query {
  createGithubIssue(owner: String!, repo: String!, title: String!, body: String!): Issue!
  getExampleHtml: String!
  getRandomImage(width: Int!, height: Int!): Image!
  getRandomQuote: Quote!
}

type Image {
  contentType: String!
  data: String!
}

type Issue {
  title: String!
  body: String!
  url: String
}

type Quote {
  quote: String!
  author: String!
}

The extraneous types do indeed need to be extracted from the wasm and included in the metadata, so that the host functions that use them can operate correctly. However, since they aren't used in any types that are inputs or outputs of the query functions, then they shouldn't be be projected to GraphQL.

This could be nuanced. For example, if one actually returned the Response object, then indeed that object and any of its dependencies would need schema.