[BUGFIX] Handle uploaded files in EXT:form

With the migration to native ServerRequestInterface, EXT:form isn't
able to detect uploaded files anymore. The `arguments` property from
the underlying Extbase request object is obtained, which contains
information about uploaded files in a wrong structure.
Therefore, the arguments are merged with the uploaded files array
instead.

Since uploaded files are converted to a `UploadedFile` object,
EXT:form's `UploadedFileReferenceConverter` is adapted to be able to
handle said objects as well.

Resolves: #100362
Releases: main
Change-Id: I07f8ce47b9cdd2334a8bb665df82d83789c9bf19
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78336


Tested-by: Kevin Appelt <kevin.appelt@icloud.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Kevin Appelt <kevin.appelt@icloud.com>
Reviewed-by: Benni Mack <benni@typo3.org>