Add empty data guard in MoreModal columnData computed property

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/Discover/Conformance/MoreModal.vue

@@ -200,6 +200,7 @@ const caseData = computed(() => {
 
 const columnData = computed(() => {
   const data = JSON.parse(JSON.stringify(props.cases)); // Deep copy the original cases data
+  if (!data || data.length === 0) return [];
   const facetName = (facName) =>
     facName
       .trim()