Can download files on Android app without permission

Summary:

If the owner of a file - of type PDF, document, image or presentation - shares it with a user and disable download, the user can still download it using the Android app.

Steps To Reproduce:

1. As user1, in the "Files" app, create a folder containing files of different formats (PDF, .odt, .png, .odp...)
2. Share the folder to user2 and uncheck "Allow download" (repeat this step twice as unchecking the box doesn't apply the first time)
3. As user2, in the Android app, open: - a PDF: in the viewer click the top right menu, choose "Download as" and select "PDF document" or "PDF document as...". You receive a "Download completed" notification and can open and save the file on your phone. - a .odp: same as above