[J5.2] Cassiopeia - Only add margin to system message container if it contains a joomla-alert#44222

pe7er merged 3 commits intojoomla:5.2-devjoomla/joomla-cms:5.2-devfrom

coolcat-creations:5.2-dev-fix-alert-margincoolcat-creations/joomla-cms:5.2-dev-fix-alert-marginCopy head branch name to clipboard