Improvements - Fluid Topics - 5.2

Improves error messages in the Page designer's Upload/Download menu.

Updates the layout of the modal used in the Upload/Download feature of the Page designer.

Documentation links: Upload and download pages 

Adds es_MX to the list of available interface languages.

Adds the possibility to use official labels in the Localized label component, and in some of the default components of the designed pages.

Documentation links: Localize pages