fixed name of icon to match new one from iconset #4311

git-svn-id: svn://develop.studip.de/studip/trunk@31655 c5b85792-5220-0410-ad23-ed5b6b8ad999
changed to new icon created for this function #4311

git-svn-id: svn://develop.studip.de/studip/trunk@31656 c5b85792-5220-0410-ad23-ed5b6b8ad999