[BUGFIX] Use full height for link browser

The link browser now uses the full height again
by fully utilizing the flexbox functionality and
wrapping the content in <div class="element-browser">

This behaviour is now consistent with the File / Record
selector which already takes up the full height.

Resolves: #93374
Releases: master
Change-Id: I7c435b4142b54b0a809c579eac9d1e0095ed691e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67540


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>