lib-storage: Verify that with SEARCH HEADER the header name is valid UTF-8.
lib-storage: Verify that with SEARCH HEADER the header name is valid UTF-8.

jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch