[TASK] Remove wrong deprecation comment in EXT:impexp

Resolves: #56829
Releases: 6.2
Change-Id: I7e710e1e901c0aa9a29e58aaeb29edea83a47238
Reviewed-on: https://review.typo3.org/28306
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer