Fix invisible power levels tile when showing hidden events (#9162)

* Fix invisible power levels tile when showing hidden events

* Add regression test

test/events/EventTileFactory-test.ts

@@ -0,0 +1,36 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { EventType, MatrixEvent } from "matrix-js-sdk/src/matrix";
+
+import { JSONEventFactory, pickFactory } from "../../src/events/EventTileFactory";
+import { createTestClient } from "../test-utils";
+
+const roomId = "!room:example.com";
+
+describe("pickFactory", () => {
+    it("should return JSONEventFactory for a no-op m.room.power_levels event", () => {
+        const cli = createTestClient();
+        const event = new MatrixEvent({
+            type: EventType.RoomPowerLevels,
+            state_key: "",
+            content: {},
+            sender: cli.getUserId(),
+            room_id: roomId,
+        });
+        expect(pickFactory(event, cli, true)).toBe(JSONEventFactory);
+    });
+});