Use the SDK's offline detection everywhere (except for restarting the sync loop). (#4472)

* Use the SDK's offline state to drive the offline indicator.

* Only use network reachability for restarting the sync loop, use the homeserver reachability for requests.

* Add a separate indicator to distinguish when the server is unreachable but the device is online.

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -16,7 +16,6 @@ typealias RoomScreenViewModelType = StateStoreViewModel<RoomScreenViewState, Roo
 class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol {
     private let clientProxy: ClientProxyProtocol
     private let roomProxy: JoinedRoomProxyProtocol
-    private let appMediator: AppMediatorProtocol
     private let appSettings: AppSettings
     private let analyticsService: AnalyticsService
     private let userIndicatorController: UserIndicatorControllerProtocol
@@ -54,14 +53,12 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
          roomProxy: JoinedRoomProxyProtocol,
          initialSelectedPinnedEventID: String?,
          ongoingCallRoomIDPublisher: CurrentValuePublisher<String?, Never>,
-         appMediator: AppMediatorProtocol,
          appSettings: AppSettings,
          appHooks: AppHooks,
          analyticsService: AnalyticsService,
          userIndicatorController: UserIndicatorControllerProtocol) {
         clientProxy = userSession.clientProxy
         self.roomProxy = roomProxy
-        self.appMediator = appMediator
         self.appSettings = appSettings
         self.analyticsService = analyticsService
         self.userIndicatorController = userIndicatorController
@@ -179,7 +176,7 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
         }
         .store(in: &cancellables)
         
-        appMediator.networkMonitor.reachabilityPublisher
+        clientProxy.homeserverReachabilityPublisher
             .filter { $0 == .reachable }
             .receive(on: DispatchQueue.main)
             .sink { [weak self] _ in
@@ -413,13 +410,12 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
 
 extension RoomScreenViewModel {
     static func mock(roomProxyMock: JoinedRoomProxyMock,
-                     clientProxyMock: ClientProxyMock = ClientProxyMock(),
+                     clientProxyMock: ClientProxyMock = ClientProxyMock(.init()),
                      appHooks: AppHooks = AppHooks()) -> RoomScreenViewModel {
         RoomScreenViewModel(userSession: UserSessionMock(.init(clientProxy: clientProxyMock)),
                             roomProxy: roomProxyMock,
                             initialSelectedPinnedEventID: nil,
                             ongoingCallRoomIDPublisher: .init(.init(nil)),
-                            appMediator: AppMediatorMock.default,
                             appSettings: ServiceLocator.shared.settings,
                             appHooks: appHooks,
                             analyticsService: ServiceLocator.shared.analytics,