fix issue when 443 port is used

fix issue when 443 port is used

The reason for this issue was that the dart Uri.hasPort[0] property
is queried when checking if the passed URL has no port added and thus
the implied 8006 port should be added. For https and port 443 the
port is detected as "default" and omitted, thus this is always false
for that, argh!

Just use a simple regex on the original trimmed origin text.
IPv6 must be wrapped in brackets so [::1] or [::1]:443 is also
correctly detected.

[0]: https://api.dart.dev/stable/2.9.1/dart-core/Uri/hasPort.html

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>