[TASK] Unused $uploadedFiles in DataHandler

Variable $uploadedFiles is carried around in
DataHandler through various methods, but is in
fact never used since TCA type=group with
internal_type=file has been dropped in v10.

The patch drops that argument. All method changes
are detail implementations within DataHandler and
either protected or marked @internal, the change
does not raise backwards compatibility issues.

Change-Id: I4ca56005d9e52255d3168358d16bbb66347d8974
Resolves: #95264
Related: #87428
Releases: master
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71115


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>