[BUGFIX] Use correct storage when getting public url of processed file

If the processed file object is marked configured to use the original
file we have to ensure the right storage is used when creating the
publicUrl.

Resolves: #69833
Releases: master, 6.2
Change-Id: Iba0b4c7b8ef8b65cceae86ada0a7c7e85f338fdf
Reviewed-on: http://review.typo3.org/43364


Reviewed-by: Nicole Cordes <typo3@cordes.co>
Tested-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Sascha Egerer <sascha@sascha-egerer.de>
Reviewed-by: Markus Sommer <markussom@posteo.de>
Tested-by: Markus Sommer <markussom@posteo.de>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>