IOS-5035 Fix empty state flash on chat load

Move dataLoaded flag after updateMessages() to prevent empty state from showing while messages are being processed. This eliminates the brief flash of empty state UI when opening chats with existing messages.

Author: ignatovv

Anytype/Sources/PresentationLayer/Modules/Chat/ChatViewModel.swift

@@ -256,11 +256,11 @@ final class ChatViewModel: MessageModuleOutput, ChatActionProviderHandler {
                 let prevChatIsEmpty = self.messages.isEmpty
 
                 self.messages = messages
-                self.dataLoaded = true
                 if prevChatIsEmpty {
                     firstUnreadMessageOrderId = chatState?.messages.oldestOrderID
                 }
                 await updateMessages()
+                self.dataLoaded = true
                 if prevChatIsEmpty {
                     if let oldestOrderId = chatState?.messages.oldestOrderID, let message = messages.first(where: { $0.message.orderID == oldestOrderId}) {
                         collectionViewScrollProxy.scrollTo(itemId: message.message.id, position: .center, animated: false)