DateHelperService.parseTime('4:00') returns time as '00:00:00'

[altso]

Reproduction link

https://stackblitz.com/edit/ng-zorro-antd-start-ewrzkm

Steps to reproduce

  fdescribe('ParseTime', () => {
    beforeEach(() => {
      injector = TestBed.configureTestingModule({
        imports: [NzI18nModule]
      });

      dateHelper = injector.get(DateHelperService);
    });

    it('should parse custom time', () => {
      expect(dateHelper.parseTime('14:00')?.toTimeString().substr(0, 8)).toBe('14:00:00'); -- passes
      expect(dateHelper.parseTime('4:00')?.toTimeString().substr(0, 8)).toBe('04:00:00'); -- fails
    });
  });

What is expected?

dateHelper.parseTime('4:00') to return 04:00

What is actually happening?

dateHelper.parseTime('4:00') returns 00:00

Environment	Info
ng-zorro-antd	8.5.2
Browser	Chrome

---

This affects the functionality of time picker. If you enter '4:00' without leading zero manually, it will reset to '00:00' on blur.

Please see the tests here: altso@50cd9d9