[BUGFIX] Error message in RTE, if I want to insert a Custom Item

Wrong wizard name is used.

Releases: master, 7.0
Resolves: #63938
Change-Id: If8ce8a6efb7ef6b96cc2ce904ab0eb8953492f07
Reviewed-on: http://review.typo3.org/35568
Reviewed-by: Stanislas Rolland <typo3@sjbr.ca>
Tested-by: Stanislas Rolland <typo3@sjbr.ca>