[BUGFIX] Typo in drag-drop area

Fixed typo from
"Drop & Drop to upload files"
to
"Drag & drop to upload files"

Resolves: #55756
Releases: 6.2
Change-Id: I35ebde8ee46fe673764c25019551130810241677
Reviewed-on: https://review.typo3.org/27441
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring