[BUGFIX] Remove unused ExtJS inclusion in System->Log

Resolves: #82908
Releases: master
Change-Id: I96d661e294a737e36a084d4fa7423cc9257d1578
Reviewed-on: https://review.typo3.org/54542


Reviewed-by: Markus Sommer <markus.sommer@typo3.org>
Tested-by: Markus Sommer <markus.sommer@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>