changed to new icon created for this function #4311

git-svn-id: svn://develop.studip.de/studip/trunk@31657 c5b85792-5220-0410-ad23-ed5b6b8ad999
fixes #4647 #4640, dialog now working without js as well

git-svn-id: svn://develop.studip.de/studip/trunk@31658 c5b85792-5220-0410-ad23-ed5b6b8ad999