Inspect corner case with revoked userid, which is self-certified afterwards.

[ni4]

Description

Right now we mark userid as revoked if it has at least one valid user-certification revocation. However, it seems that other implementations allows such userids (but only if new self-certification is issued after the revocation).

See more details here: https://bugzilla.mozilla.org/show_bug.cgi?id=1695724

[ni4]

Some more details: key contains userid revocations, not the key revocations. So, since key itself wasn't compromised, and user just revoked and then certified userid back, we should not mark such userid (and key) as invalid.