fix: change FetchListDataSourceError to a class declaration (#2614)

* refactor: change FetchListDataSourceError to a class declaration

* fix: update export method for FetchListDataSourceError in the package

Author: Diaan

.changeset/huge-mangos-walk.md

@@ -0,0 +1,5 @@
+---
+'@sl-design-system/data-source': patch
+---
+
+Changed the way FetchListDataSourceError is exported in the package.

packages/components/data-source/src/fetch-list-data-source.ts

@@ -68,14 +68,14 @@ export interface FetchListDataSourceOptions<T> extends ListDataSourceOptions<T>
 
 export type FetchListDataSourceEvent = CustomEvent<FetchListDataSourceCallbackOptions>;
 
-export const FetchListDataSourceError = class extends Error {
+export class FetchListDataSourceError extends Error {
   constructor(
     message: string,
     public response: Response
   ) {
     super(message);
   }
-};
+}
 
 /** Symbol used as a placeholder for items that are being loaded. */
 export const FetchListDataSourcePlaceholder = Symbol('FetchListDataSourcePlaceholder');