Prevent default form submission in MemberListView (#30312)

test/unit-tests/components/views/rooms/memberlist/MemberListView-test.tsx

@@ -8,7 +8,7 @@ Please see LICENSE files in the repository root for full details.
 */
 
 import { act } from "react";
-import { waitFor } from "jest-matrix-react";
+import { waitFor, fireEvent } from "jest-matrix-react";
 import { type Room, type RoomMember, MatrixEvent } from "matrix-js-sdk/src/matrix";
 import { type JSX } from "react";
 
@@ -154,6 +154,16 @@ describe("MemberListView and MemberlistHeaderView", () => {
                 expect(root.container.querySelector(".mx_PresenceIconView_unavailable")).not.toBeNull();
             });
         });
+
+        it("should prevent default form submission", async () => {
+            const { root } = rendered;
+            const form = root.container.querySelector("form");
+            expect(form).not.toBeNull();
+            const submitEvent = new Event("submit", { bubbles: true, cancelable: true });
+            const preventDefaultSpy = jest.spyOn(submitEvent, "preventDefault");
+            fireEvent(form!, submitEvent);
+            expect(preventDefaultSpy).toHaveBeenCalled();
+        });
     });
 
     describe.each([true, false])("does order members correctly (presence %s)", (enablePresence) => {