Datepicker loses time when moving to the next month and picking a date.

[LeahPike]

Bug description:
The time is lost when moving to the next month and picking a date.

This can be replicated on the example on this page:
https://valor-software.com/ngx-bootstrap/#/components/datepicker?tab=overview#with-timepicker

1. Click on the date picker
2. Enter a time of 9 am
3. Click on a date
4. Click on the date picker
5. Click on the right arrow to step into the next month
6. Click on another date

Expected behavior

The time of 9 am should be kept, it should not reset.