Update OIDC presentation (#987)

* Present OIDC directly on the ServerConfirmationScreen.

Read the actual window from the view.

* Pop back to the confirmation screen when a user enters an MXID that needs OIDC.

* Remove OIDC error handling from the login screen.

ElementX/Sources/Screens/Authentication/ServerConfirmationScreen/View/ServerConfirmationScreen.swift

@@ -34,6 +34,10 @@ struct ServerConfirmationScreen: View {
                 .readableFrame()
                 .background(Color.element.background.ignoresSafeArea())
         }
+        .introspectViewController { viewController in
+            guard let window = viewController.view.window else { return }
+            context.send(viewAction: .updateWindow(window))
+        }
     }
     
     /// The main content of the view to be shown in a scroll view.