[BUGFIX] Improved visibility error message in install tool

Prevent double scrolling bars in error messages.
For example in install tool modals.

Resolves: #88093
Releases: master, 9.5
Change-Id: I32b70197cede4f652c864774bcbf24cea5120d90
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60398


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Steffen Frese <steffenf14@gmail.com>
Tested-by: Tobi Kretschmann <tobi@tobishome.de>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Steffen Frese <steffenf14@gmail.com>
Reviewed-by: Tobi Kretschmann <tobi@tobishome.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>