chore: extract json-api from core

Signed-off-by: Jari Kolehmainen <jari.kolehmainen@gmail.com>

packages/core/src/common/fetch/fetch.injectable.ts

@@ -3,14 +3,13 @@
  * Licensed under MIT License. See LICENSE in root directory for more information.
  */
 import { getInjectable } from "@ogre-tools/injectable";
-import type { RequestInit, Response } from "@k8slens/node-fetch";
 import fetch from "@k8slens/node-fetch";
 
-export type Fetch = (url: string, init?: RequestInit) => Promise<Response>;
+export type Fetch = typeof fetch;
 
 const fetchInjectable = getInjectable({
   id: "fetch",
-  instantiate: () => fetch as Fetch,
+  instantiate: () => fetch,
   causesSideEffects: true,
 });