--http-proxy-user-pass: allow to specify in either order with --http-proxy

--http-proxy-user-pass: allow to specify in either order with --http-proxy

Previously, when using a third argument to --http-proxy other
than auto/auto-nct, order did matter between --http-proxy and
--http-proxy-user-pass. Always prefer --http-proxy-user-pass
when given.

Change-Id: I6f402db2fb73f1206fbc1139c47d2bf4378376fa
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20240122092122.8591-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28099.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit a634cc5eccd55f1d14197da7376bb819bdf72cb6)