net-mgmt/icinga2: Update to 2.14.6

This includes a security update for Icinga2 built with OpenSSL < 1.1.0.
As everything we shipped since 12.0 included OpenSSL >= 1.1.1a and we
don't provided a supported version of OpenSSL < 1.1.0 in ports since
January 2020 I opted not to make this a security update and not create a
VuXML entry for this.

Security: https://icinga.com/blog/cve-2025-48057/