[BUGFIX] Element browser: importing a selection of images does not work

When using the element browser wizard to import a selection of images
into an images or text+images content element, the list of uid's of
images to import is malformed and insertion fails.

Releases: master
Resolves: #65109
Change-Id: Ib32043507ef0dd6969c60d57738eaf16f2597192
Reviewed-on: http://review.typo3.org/36960


Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Andy Grunwald <andygrunwald@gmail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Frans Saris <franssaris@gmail.com>
Tested-by: Markus Klein <klein.t3@reelworx.at>