Live location sharing - stop sharing to beacons in rooms you left (#8187)

* remove beacons on membership changes

* add addMembershipToMockedRoom test util

Signed-off-by: Kerry Archibald <kerrya@element.io>

* test remove beacons on membership changes

Signed-off-by: Kerry Archibald <kerrya@element.io>

* removelistener

Signed-off-by: Kerry Archibald <kerrya@element.io>

test/test-utils/room.ts

@@ -0,0 +1,34 @@
+/*
+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,
+} from "matrix-js-sdk/src/matrix";
+
+import { mkEvent } from "./test-utils";
+
+export const makeMembershipEvent = (
+    roomId: string, userId: string, membership = 'join',
+) => mkEvent({
+    event: true,
+    type: EventType.RoomMember,
+    room: roomId,
+    user: userId,
+    skey: userId,
+    content: { membership },
+    ts: Date.now(),
+});
+