[BUGFIX] Add support for float values to arrayExport

ArrayUtility::arrayExport() must support float values too.

Change-Id: Ibfb0dfa3b7d8f584d41ff01f49a40dbbd991a66e
Releases: 6.2, 6.1, 6.0
Fixes: #48114
Reviewed-on: https://review.typo3.org/20704
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring