[BUGFIX] Compare field names without configuration

With patch https://review.typo3.org/34019/ the function
ExtensionManagementUtility::removeDuplicatesForInsertion was rewritten.
But the rewrite fails for fields with additional configuration and
returns wrong field information.

Resolves: #65480
Releases: master, 6.2
Change-Id: I9aa35cd7ef5142e7b57489bf6e19a78811b8c335
Reviewed-on: http://review.typo3.org/38528


Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>