fix(catalyst): TRAC-279 default brand PLP sort to featured (#3021)

Brand PLPs were defaulting to relevance, which is intended for search
results. Pin the default to featured so unranked brand pages match the
rest of the catalog.

Author: mfaris9

.changeset/fix-brand-plp-sort.md

@@ -0,0 +1,5 @@
+---
+"@bigcommerce/catalyst-core": patch
+---
+
+Default brand PLP sort to `featured` to honor the merchant's product sort order.

core/app/[locale]/(default)/(faceted)/brand/[slug]/page.tsx

@@ -116,12 +116,14 @@ export default async function Brand(props: Props) {
 
     const loadSearchParams = await createBrandSearchParamsLoader(slug, customerAccessToken);
     const parsedSearchParams = loadSearchParams?.(searchParams) ?? {};
+    const sort = typeof searchParams.sort === 'string' ? searchParams.sort : 'featured';
 
     const search = await fetchFacetedSearch(
       {
         ...searchParams,
         ...parsedSearchParams,
         brand: [slug],
+        sort,
       },
       currencyCode,
       customerAccessToken,