[BUGFIX] Ensure to override JSwindow custom parameters

Currently "typolink.JSwindow_params" allows to set custom parameters
when opening a link within a JS-based popup. When linking an image,
the custom parameters have been added as well.

Resolves: #21302
Releases: master
Change-Id: Ia3ec655d8fe5536fd14564383da41a3fdfbb86c2
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63921


Tested-by: Susanne Moog <look@susi.dev>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>