security/openvpn-devel: upgrade port to git commit 1e7b9a0fb0 (2.7_beta1, 2025-09-03)

This commit brings the port to "openvpn 2.7_beta1".

New features alpha3 -> beta1 are

• a large number of signed/unsigned related warnings have been fixed
• bugfixes in --dns-updown script for linux systems using resolvconf
• rewrite of the management interface "bytecount" infastructure to better interact with DCO
• PUSH_UPDATE server support (via management interface)
• introduction of route_redirect_gateway_ipv4 and _ipv6 env variables
• speeding up t_client tests by reducing per-test startup delay 3s -> 1s

The biggest noticeable difference in beta1 is the reformatting using
clang-format, leaving uncrustify as that wasn't stable across versions.

PR: 289315