Element Call video rooms (#9267)

* Add an element_call_url config option

* Add a labs flag for Element Call video rooms

* Add Element Call as another video rooms backend

* Consolidate event power level defaults

* Remember to clean up participantsExpirationTimer

* Fix a code smell

* Test the clean method

* Fix some strict mode errors

* Test that clean still works when there are no state events

* Test auto-approval of Element Call widget capabilities

* Deduplicate some code to placate SonarCloud

* Fix more strict mode errors

* Test that calls disconnect when leaving the room

* Test the get methods of JitsiCall and ElementCall more

* Test Call.ts even more

* Test creation of Element video rooms

* Test that createRoom works for non-video-rooms

* Test Call's get method rather than the methods of derived classes

* Ensure that the clean method is able to preserve devices

* Remove duplicate clean method

* Fix lints

* Fix some strict mode errors in RoomPreviewCard

* Test RoomPreviewCard changes

* Quick and dirty hotfix for the community testing session

* Revert "Quick and dirty hotfix for the community testing session"

This reverts commit 37056514fbc040aaf1bff2539da770a1c8ba72a2.

* Fix the event schema for org.matrix.msc3401.call.member devices

* Remove org.matrix.call_duplicate_session from Element Call capabilities

It's no longer used by Element Call when running as a widget.

* Replace element_call_url with a map

* Make PiPs work for virtual widgets

* Auto-approve room timeline capability

Because Element Call uses this now

* Create a reusable isVideoRoom util

test/test-utils/test-utils.ts

@@ -99,7 +99,7 @@ export function createTestClient(): MatrixClient {
         },
 
         getPushActionsForEvent: jest.fn(),
-        getRoom: jest.fn().mockImplementation(mkStubRoom),
+        getRoom: jest.fn().mockImplementation(roomId => mkStubRoom(roomId, "My room", client)),
         getRooms: jest.fn().mockReturnValue([]),
         getVisibleRooms: jest.fn().mockReturnValue([]),
         loginFlows: jest.fn(),
@@ -335,8 +335,10 @@ export function mkRoomMember(roomId: string, userId: string, membership = "join"
         name: userId,
         rawDisplayName: userId,
         roomId,
+        events: {},
         getAvatarUrl: () => {},
         getMxcAvatarUrl: () => {},
+        getDMInviter: () => {},
     } as unknown as RoomMember;
 }