Add a service and flow coordinator for the LinkNewDevice feature. (#4859)

* Add a LinkNewDeviceService that exposes the SDK's grant QR code login methods.

* Add a flow coordinator for linking a new device.

Changes the presentation too.

ElementX/Sources/Services/Client/ClientProxy.swift

@@ -715,13 +715,9 @@ class ClientProxy: ClientProxyProtocol {
             return .failure(.sdkError(error))
         }
     }
-
-    func logout() async {
-        do {
-            try await client.logout()
-        } catch {
-            MXLog.error("Failed logging out with error: \(error)")
-        }
+    
+    func linkNewDeviceService() -> LinkNewDeviceService {
+        LinkNewDeviceService(handler: client.newGrantLoginWithQrCodeHandler())
     }
     
     func deactivateAccount(password: String?, eraseData: Bool) async -> Result<Void, ClientProxyError> {
@@ -734,6 +730,14 @@ class ClientProxy: ClientProxyProtocol {
         }
     }
     
+    func logout() async {
+        do {
+            try await client.logout()
+        } catch {
+            MXLog.error("Failed logging out with error: \(error)")
+        }
+    }
+    
     func setPusher(with configuration: PusherConfiguration) async throws {
         try await client.setPusher(identifiers: configuration.identifiers,
                                    kind: configuration.kind,