feat(client): Handle empty responses

[rozzilla]

Given an OpenAPI schema containing no body (f.e. for a 204 status code):

"/public/internal/test": {
      "get": {
        "responses": {
          "204": {
            "description": "Default Response"
          }
        }
      }
    },

We currently return export type GetPublicInternalTestResponses = undefined; while we should return this type:export type GetPublicInternalTaxAccountsResponses = FullResponse<unknown, 204>

P.S. This has already been addressed on #2338 but only for the front-end (not the TypeScript types).

[leorossi]

This is similar to #2338 where the fix was in the implementation.

Having something like this for the response would help