[TASK] Install: Update TTFdpi test description text

Resolves: #49267
Releases: 6.2
Change-Id: Iffe09f072bda483ffa5f5be766ff0e84c3e025de
Reviewed-on: https://review.typo3.org/21604
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe