message: fix: use MockedClass
diff: @@ -29,8 +29,8 @@ describe("FileClient", () => {
  expect(mockClient.getLogs()[0].method).toBe("post");
  });
  it("should pass file object includes name and data as a param to the http client", () => {
  - const mockFormData = (FormData as jest.Mock<FormData>).mock.instances[0];
  - expect(mockFormData.append.mock.calls[0]).toEqual([
  + const MockFormData = FormData as jest.MockedClass<typeof FormData>;
  + expect(MockFormData.prototype.append.mock.calls[0]).toEqual([
  "file",
  params.file.data,
  params.file.name
  