message: refactor(language-service): remove non-null assertion on MockHost member
  `nodeModulesPath` is now initialized in the constructor, so there is no
  need for a non-null assertion as suggested in
  PR Close
diff: @@ -66,8 +66,7 @@ missingCache.set('/node_modules/@angular/forms/src/directives/form_interface.met
  export class MockTypescriptHost implements ts.LanguageServiceHost {
  private angularPath: string|undefined;
  - // TODO(issue/24571): remove '!'.
  - private nodeModulesPath !: string;
  + private nodeModulesPath: string;
  private scriptVersion = new Map<string, number>();
  private overrides = new Map<string, string>();
  private projectVersion = 0;
  