dayjs('05:00', 'HH:mm') is invalid

**Describe the bug**
dayjs('05:00', 'HH:mm') is invalid

**Expected behavior**
I would expect it to be valid

**Information**
- Day.js Version 1.11.10

Start by reproducing the reported Day.js 1.11.10 behavior for dayjs('05:00', 'HH:mm') and inspect the date parsing entry point used by the format argument. Confirm the expected valid result with a focused regression test; done means the input is accepted without breaking existing formatted-date parsing tests.

Written by the indexing model from the issue text.