BUG: DateTimeEditor does not show a leading 0 for minutes < 10

[erkenes]

Description

The DateTimeEditor does not display a leading 0 for minutes < 10 at the beginning.

Steps to Reproduce

1. Open the _hiddenBeforeDateTime input (or another DateTime-Editor) and click on the time
2. Set a time with minutes between 0 and 9
3. Click on the date again

Expected behavior

If I set "02:01" as the time it should show "02:01" and not "02:1".

Actual behavior

Should not the hour have a leading zero too?

Affected Versions

Neos: 8.3.12

UI: 8.3.7