message: test(docs-infra): use existing `MockLogger` class in `SwUpdatesService` tests
  Since we have a `MockLogger` class in `src/testing/`, there is no need
  to create a new `MockLogger` class for the `SwUpdatesService` unit
  tests.
  This commit switches to using the `MockLogger` class from
  `src/testing/`.
  PR Close
diff: @@ -4,6 +4,7 @@ import { SwUpdate } from '@angular/service-worker';
  import { Subject } from 'rxjs';
  import { Logger } from 'app/shared/logger.service';
  +import { MockLogger } from 'testing/logger.service';
  import { SwUpdatesService } from './sw-updates.service';
  @@ -204,10 +205,6 @@ class MockApplicationRef {
  isStable = new Subject<boolean>();
  }
  -class MockLogger {
  - log = jasmine.createSpy('MockLogger.log');
  -}
  -
  class MockSwUpdate {
  $$availableSubj = new Subject<{available: {hash: string}}>();
  $$activatedSubj = new Subject<{current: {hash: string}}>();
  