[TASK] Make CharsetConverterTest notice free

Resolves: #84366
Releases: master
Change-Id: I0dcd7f4277c4576938dbb6b94adf5c40d6424dfe
Reviewed-on: https://review.typo3.org/56248


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>