[BUGFIX] System information looks ugly

Install tool -> important actions -> system information does
not break correctly on the definition list. Adapt css a bit.

Resolves: #49748
Related: #49162
Releases: 6.2

Change-Id: Ia2f1c5e4152c238e9c53fb383588fd12d72df1d8
Reviewed-on: https://review.typo3.org/22053
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring