feat(store): testing - expose MockStore provider (#2331)

Closes #2328

Author: alex-okrushko

modules/store/testing/src/testing.ts

@@ -23,6 +23,7 @@ export function provideMockStore<T = any>(
   return [
     ActionsSubject,
     MockState,
+    MockStore,
     { provide: INITIAL_STATE, useValue: config.initialState || {} },
     { provide: MOCK_SELECTORS, useValue: config.selectors },
     { provide: StateObservable, useClass: MockState },