Re-scope sortedDates usage

sortedDates is not used if the resource is not versioned. The premature
null check in the case of unversioned resources resulted in an error on
the groups page, which does not use versioned resources.

static-site/src/components/ListResources/useDataFetch.ts

@@ -63,18 +63,12 @@ function partitionByPathogen(
   versioned: boolean,
 ) {
   return Object.entries(pathVersions).reduce((store: Record<string, Resource[]>, [name, dates]) => {
-    const sortedDates = [...dates].sort();
-
     const nameParts = name.split('/');
 
     if (nameParts[0] === undefined) {
       throw new InternalError(`Name is not properly formatted: '${name}'`);
     }
 
-    if (sortedDates[0] === undefined) {
-      throw new InternalError("Resource does not have any dates.");
-    }
-
     const groupName = nameParts[0];
 
     const resourceDetails: Resource = {
@@ -85,6 +79,11 @@ function partitionByPathogen(
       url: `/${pathPrefix}${name}`,
     };
     if (versioned) {
+      const sortedDates = [...dates].sort();
+      if (sortedDates[0] === undefined) {
+        throw new InternalError("Resource does not have any dates.");
+      }
+
       resourceDetails.lastUpdated = sortedDates.at(-1);
       resourceDetails.firstUpdated = sortedDates[0];
       resourceDetails.dates = sortedDates;