Add client option to pass custom RequestInit object into fetch requests for supported implementations - refactor test to use own server/endpoint

Author: mellster2012

packages/openapi-fetch/test/common/create-client.test.ts

@@ -1,8 +1,7 @@
 import { describe, expect, test } from "vitest";
 import { createObservedClient } from "../helpers.js";
-import createClient, { type FetchOptions, type HeadersOptions } from "../../src/index.js";
+import { type FetchOptions, type HeadersOptions } from "../../src/index.js";
 import type { paths } from "./schemas/common.js";
-import { Agent } from "undici";
 
 describe("createClient options", () => {
   test("baseUrl", async () => {