test: fix fetch related tests

server/__mocks__/fetch-with-proxy.ts

@@ -0,0 +1,9 @@
+import fetchMock from "jest-fetch-mock";
+
+fetchMock.enableMocks();
+
+// changes default behavior of fetchMock to use the real 'fetch' implementation.
+// Mocks can now be enabled in each individual test with fetchMock.doMock()
+fetchMock.dontMock();
+
+export default fetch;