[BUGFIX] Prevent division by zero when scaling image

Prevents multiple division by zero errors when scaling
images, by checking that the input image size is valid
(meaning non-zero) before attempting to calculate
the ratio for scaling - because the ratio is based on the
input size parameters that must not be zero.

Change-Id: I33fd3e49a1b3dcdc319309af736a9d785130af94
Releases: master, 9.5, 8.7
Resolves: #87954
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60299


Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>