Fix early_data age calculation

Fix early_data age calculation

The ticket_age/age_add values use ms granualarity. We were incorrectly
treating them as seconds and so the ticket was always being rejected for
early data. We also clarify a comment which could have been the source of
the confusion.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20387)