[TASK] Use l10nmode copy for datetime

Resolves: #60695
Change-Id: I736f478cdac42c3d617d5da7fdca3d33c10239e9
Reviewed-on: http://review.typo3.org/35680
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>