[BUGFIX] Adjust UserAgent checks in RTE to detect Edge correctly

Resolves: #70373
Releases: master, 7.6, 6.2
Change-Id: I8cb505a051ecfbc0f423d32cbc121545cec35bf4
Reviewed-on: https://review.typo3.org/47037


Reviewed-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Tested-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Daniel Maier <dani-maier@gmx.de>
Tested-by: Daniel Maier <dani-maier@gmx.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>