[BUGFIX] Fix spelling issue in Install Tool

compatibilyt -> compatibility

Change-Id: I3bed3fa4b0477870f393498a44c5cb766d1b7c33
Resolves: #49393
Releases: 6.2, 6.1
Reviewed-on: https://review.typo3.org/21648
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters