CustomParseFormat does not parse UTC offset in strict mode

[cvbge]

Describe the bug

// From CustomParseFormat documentation, assertion passes:
assert(dayjs("05/02/69 1:02:03 PM -05:00", "MM/DD/YY H:mm:ss A Z").isValid())

// Same example but with strict=true, assertion fails:
assert(dayjs("05/02/69 1:02:03 PM -05:00", "MM/DD/YY H:mm:ss A Z", true).isValid())

Expected behavior
Both should pass

Information

• Day.js Version: 1.11.13
• OS: Windows 10
• Browser: NodeJs v20.17.0
• Time zone: Europe/Warsaw UTC+2