[BUGFIX] Include jquery-ui-resizable css

The last time this css file was seen is in the old rtehtmlarea. Since
it got replaced with the new ckeditor, the css was missing and the
resize handles of the focusArea were lacking required styling.

Resolves: #90437
Releases: master, 9.5, 8.7
Change-Id: I29cd6d255e7866d91a3480ed7ce40690cefd8c51
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63326


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Susanne Moog <look@susi.dev>