Deprecation: #83976 - Moved file extension detection to FAL driver 

See forge#83976

Description 

The only object that is allowed to handle the physical file in the FAL is the driver, as it is the only instance that knows how to access the file.

The definition of the FAL driver method getFileInfoByIdentifier() is enhanced with the return value extension.

Impact 

Installations with a FAL driver getFileInfoByIdentifier() method that doesn't return the extension value will trigger a PHP E_USER_DEPRECATED error.

Affected Installations 

Installations with 3rd party FAL drivers.

Migration 

Adjust the getFileInfoByIdentifier() method of your file drivers to return the extension value.