Fix assert failure when marking order as read

WooCommerce/Classes/Model/MarkOrderAsReadUseCase.swift

@@ -25,6 +25,7 @@ struct MarkOrderAsReadUseCase {
     /// and then we compare local `orderID` with the one from remote `Note`.
     /// If they match we mark it as read.
     /// Returns syncronized note if marking was successful and error if some error happened
+    @MainActor
     static func markOrderNoteAsReadIfNeeded(stores: StoresManager, noteID: Int64, orderID: Int) async -> Result<Note, Error> {
         let syncronizedNoteResult: Result<Note, Error> = await withCheckedContinuation { continuation in
             let action = NotificationAction.synchronizeNotification(noteID: noteID) { syncronizedNote, error in