fix(guidelines): update about modal
fix(guidelines): update about modal

update About Modal css to meet code guidelines

fabric8io/fabric8-ui,fabric8io/fabric8-ui,fabric8-ui/fabric8-ui,fabric8-ui/fabric8-ui,fabric8io/fabric8-ui,fabric8io/fabric8-ui,fabric8-ui/fabric8-ui,fabric8-ui/fabric8-ui,fabric8io/fabric8-ui,fabric8-ui/fabric8-ui