[TASK] Cleanup InfoBoxViewHelper

* Encode title and message in case they are provided as vh argument.
* Minor code cleanup

Resolves: #71406
Releases: master
Change-Id: Ice28ed261c294c0164e06f24ed90cca31ddc1707
Reviewed-on: https://review.typo3.org/44610


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>
Tested-by: Frank Nägler <frank.naegler@typo3.org>