[BUGFIX] Late bind drag uploader

If TCA with a file upload is used within IRRE (e.g. as done by
EXT:news), creating a new record or opening an existing record now sets
up the drag uploader.

As the DragUploader module is loaded independently from the FormEngine
main module, loading order may vary, rendering an event-based solution
unstable. To solve this issue without any major refactorings, a
MutationObserver is installed by the DragUploader module.

Resolves: #97676
Releases: main, 11.5
Change-Id: I36a3922999842f4d0bddfc7e4b148ec39880d9df
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74813


Tested-by: core-ci <typo3@b13.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>