add a comma in CoreBanner for prettier
add a comma in CoreBanner for prettier

lyw07/kolibri,lyw07/kolibri,indirectlylit/kolibri,learningequality/kolibri,indirectlylit/kolibri,mrpau/kolibri,indirectlylit/kolibri,lyw07/kolibri,mrpau/kolibri,lyw07/kolibri,indirectlylit/kolibri,mrpau/kolibri,learningequality/kolibri,learningequality/kolibri,mrpau/kolibri,learningequality/kolibri