[BUGFIX] Fix undefined key warning in cObj->imageLinkWrap

The default configuration for JSWindow in
lib.contentElement doesn't contain the params
property, so after stdWrapping it in
ContentObjectRenderer, it becomes an empty string.

Thus, exploding it needs a fallback to prevent
PHP 8.0 undefined array key warnings.

In addition, first tests have been added for
cObj->imageLinkWrap, which cover this warning. These
tests have also found another warning for
JSwindow.altUrl_noDefaultParams, which is also
fixed now.

Resolves: #96647
Related: #96508
Releases: main, 11.5
Change-Id: I593e42e3be8ebac4e8001275f2da9d635936c79e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73175


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: physikbuddha <r.kaerner@oranto.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>