[BUGFIX] Pre-define `cropBox` in Image Manipulation

This patch pre-defines `cropBox` with an empty jQuery object to avoid
errors when starting the image cropper. A similar fix was already done
in #99953, that's why the issue doesn't pop up in v12.

Resolves: #100576
Releases: 11.5
Change-Id: I5d4fc7022a7521816ffc7762dde146256a6171ff
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78615


Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>