Improve randomString mock for better snapshots (#11375)

test/components/structures/SpaceHierarchy-test.tsx

@@ -30,11 +30,6 @@ import MatrixClientContext from "../../../src/contexts/MatrixClientContext";
 import DMRoomMap from "../../../src/utils/DMRoomMap";
 import SettingsStore from "../../../src/settings/SettingsStore";
 
-// Fake random strings to give a predictable snapshot for checkbox IDs
-jest.mock("matrix-js-sdk/src/randomstring", () => ({
-    randomString: () => "abdefghi",
-}));
-
 describe("SpaceHierarchy", () => {
     describe("showRoom", () => {
         let client: MatrixClient;