test: add mock for ResizeObserver to support unit tests

jest.setup.js

@@ -1,2 +1,10 @@
 // Learn more: https://github.com/testing-library/jest-dom
 import "@testing-library/jest-dom"
+
+class ResizeObserverMock {
+  observe() {}
+  unobserve() {}
+  disconnect() {}
+}
+
+global.ResizeObserver = ResizeObserverMock;