plugins: refactory to use default export for new backend system

Co-authored-by: Fredrik Adelöw <freben@gmail.com>
Co-authored-by: Camila Belo <camilaibs@gmail.com>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Co-authored-by: Philipp Hugenroth <philipph@spotify.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/lighthouse-backend/api-report.md

@@ -30,7 +30,8 @@ export function createScheduler(
 ): Promise<void>;
 
 // @public
-export const lighthousePlugin: () => BackendFeature;
+const lighthousePlugin: () => BackendFeature;
+export default lighthousePlugin;
 
 // (No @packageDocumentation comment for this package)
 ```

plugins/lighthouse-backend/src/index.ts

@@ -15,4 +15,4 @@
  */
 
 export * from './service/createScheduler';
-export { lighthousePlugin } from './plugin';
+export { lighthousePlugin as default } from './plugin';