Deflake Core dashboard test (#52558)

The dashboard tests are supposed to mock out API responses anyways, this test did not mock out one of API calls. We'll mock it out and this should deflake this test.

Signed-off-by: Alan Guo <aguo@anyscale.com>

Author: alanwguo

python/ray/dashboard/client/src/pages/overview/OverviewPage.component.test.tsx

@@ -3,12 +3,22 @@ import React, { PropsWithChildren } from "react";
 import { MemoryRouter } from "react-router-dom";
 import { GlobalContext } from "../../App";
 import { STYLE_WRAPPER } from "../../util/test-utils";
+import { useRayStatus } from "../job/hook/useClusterStatus";
 import { useJobList } from "../job/hook/useJobList";
 import { OverviewPage } from "./OverviewPage";
 
 jest.mock("../job/hook/useJobList");
+jest.mock("../job/hook/useClusterStatus");
+
+const mockedUseRayStatus = jest.mocked(useRayStatus);
 
 describe("OverviewPage", () => {
+  beforeEach(() => {
+    mockedUseRayStatus.mockReturnValue({
+      clusterStatus: undefined,
+    });
+  });
+
   it("renders", async () => {
     expect.assertions(3);