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/Services/Client/ClientProxy.swift

@@ -137,6 +137,11 @@ class ClientProxy: ClientProxyProtocol {
         verificationStateSubject.asCurrentValuePublisher()
     }
     
+    private let homeserverReachabilitySubject = CurrentValueSubject<NetworkMonitorReachability, Never>(.reachable)
+    var homeserverReachabilityPublisher: CurrentValuePublisher<NetworkMonitorReachability, Never> {
+        homeserverReachabilitySubject.asCurrentValuePublisher()
+    }
+    
     private let timelineMediaVisibilitySubject = CurrentValueSubject<TimelineMediaVisibility, Never>(.always)
     var timelineMediaVisibilityPublisher: CurrentValuePublisher<TimelineMediaVisibility, Never> {
         timelineMediaVisibilitySubject.asCurrentValuePublisher()
@@ -218,10 +223,10 @@ class ClientProxy: ClientProxyProtocol {
         })
         
         sendQueueStatusSubject
-            .combineLatest(networkMonitor.reachabilityPublisher)
+            .combineLatest(homeserverReachabilityPublisher)
             .debounce(for: 1.0, scheduler: DispatchQueue.main)
             .sink { enabled, reachability in
-                MXLog.info("Send queue status changed to enabled: \(enabled), reachability: \(reachability)")
+                MXLog.info("Send queue status changed to enabled: \(enabled), homeserver reachability: \(reachability)")
                 
                 if enabled == false, reachability == .reachable {
                     MXLog.info("Enabling all send queues")
@@ -926,12 +931,11 @@ class ClientProxy: ClientProxyProtocol {
             
             switch state {
             case .running, .terminated, .idle:
-                break
+                homeserverReachabilitySubject.send(.reachable)
+            case .offline:
+                homeserverReachabilitySubject.send(.unreachable)
             case .error:
                 restartSync()
-            case .offline:
-                // This needs to be enabled in the client builder first to be actually used
-                break
             }
         })
     }
@@ -1196,6 +1200,7 @@ private struct ClientProxyServices {
         let syncService = try await client
             .syncService()
             .withCrossProcessLock()
+            .withOfflineMode()
             .withSharePos(enable: true)
             .finish()