[MM-61766] Fix errcheck issues in server/channels/app/platform/link_cache.go (#29363)

server/channels/app/platform/link_cache.go

@@ -16,8 +16,8 @@ var linkCache = cache.NewLRU(&cache.CacheOptions{
 	Size: LinkCacheSize,
 })
 
-func PurgeLinkCache() {
-	linkCache.Purge()
+func PurgeLinkCache() error {
+	return linkCache.Purge()
 }
 
 func LinkCache() cache.Cache {