[BUGFIX] Remove array reset due to broken backwards compatibility

The reset breaks the mapping if a file upload should be mapped as a
property of an object.

Additionally, parts of the ext:form fix introduced with #100362
have been removed again, since uploadedFiles are now available
in arguments again.

Resolves: #102271
Releases: 12.4
Change-Id: I19a45369216c63a2d67a67c05a4b5695a0d42b2a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81594


Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Torben Hansen <derhansen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>