Update keys with origin WKD also via WKD

Additionally to the update via keyserver/LDAP server/AD, an update via
WKD is performed if the key is eligible for a WKD update. Only user IDs
with origin WKD, i.e. which were originally retrieved via WKD, are
considered for the update.

(cherry picked from commit 5f3c408b2caed5e04e48f8c35a43619464c55a56)

• GnuPG-bug-id: T5903