IMAP resource: do not prompt for password with GSSAPI auth
Summary:
GSSAPI (e.g. when used with Kerberos) does not use passwords, so make sure the user is not prompted unnecessarily.
BUG: 383279
FIXED-IN: 19.12.0
Reviewers: dvratil
Reviewed By: dvratil
Subscribers: dvratil, kde-pim
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D25499