[BUGFIX] Suggest wizard broken when used in a repeating flexform element

Get correct fieldConfig when in repeating flexform. Adjust
JavaScript a bit to make this work.

Resolves: #48474
Releases: 6.2, 6.1, 6.0
Change-Id: I7c8a5ecfc2f1d7cfb10ca86a40a3429d3a60ee1f
Reviewed-on: https://review.typo3.org/20990
Reviewed-by: Zach Davis
Tested-by: Zach Davis
Reviewed-by: Mattias Nilsson
Tested-by: Mattias Nilsson
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters