fix(mdc-slide-toggle-benchmark): remove unnecessary provider

Author: wagnermaciel

test/benchmarks/mdc/slide-toggle/app.module.ts

@@ -38,7 +38,6 @@ export class SlideToggleBenchmarkApp {
     BrowserModule,
     MatSlideToggleModule,
   ],
-  providers: [],
   bootstrap: [SlideToggleBenchmarkApp]
 })
 export class AppModule {}