Add e2e tests to bookmarking in dashboard page (#21059)

frontend/test/metabase/scenarios/dashboard/bookmarks.cy.spec.js

+import { restore, sidebar } from "__support__/e2e/cypress";
+
+describe("scenarios > dashboard > bookmarks", () => {
+  beforeEach(() => {
+    restore();
+    cy.signInAsAdmin();
+  });
+
+  it("should add and then remove bookmark", () => {
+    cy.visit("/dashboard/1");
+
+    cy.icon("ellipsis").click();
+
+    cy.findByText("Bookmark").click();
+
+    cy.visit("/collection/root");
+
+    sidebar().within(() => {
+      // Find the bookmark and click on it to visit dashboard page again
+      cy.findByText("Orders in a dashboard").click();
+    });
+
+    cy.icon("ellipsis").click();
+
+    cy.findByText("Remove bookmark").click();
+
+    cy.intercept("GET", "/api/collection/root/items?**").as(
+      "fetchRootCollectionItems",
+    );
+
+    cy.visit("/collection/root");
+
+    cy.wait("@fetchRootCollectionItems");
+
+    sidebar().within(() => {
+      cy.findByText("Orders in a dashboard").should("not.exist");
+    });
+  });
+});