accompanying course work: handle case end date is null

src/Bundle/ChillPersonBundle/Resources/public/chill/scss/accompanying_period_work.scss

@@ -37,6 +37,9 @@ div.accompanying_course_work-list {
                             border-radius: 12px;
                             border: 2px solid $chill-green;
                         }
+                        &.no-label:before {
+                            display: none;
+                        }
                     }
                 }
             }