Open recent file, already added to the project

Use case:

1. Open a file in UGENE and save the project.
2. Reopen UGENE.
   Expected state:
   • The opened file is present in the project, but it is unloaded.
   • The file is listed in the "Recent files" group on the start page.
3. Click on the file link.
   Current state: a warning message box appears.
   Expected state:
   • The file is loaded without warnings.