Feature: #89929 - Galician flag

See Issue #89929

Description

When adding a new language to a site or the system (sys_language) the Galician flag (ISO-639-1 Code “gl”) is now available for selection.

Impact

A previous error, where the flag for Greenlandic was available (ISO Code “kl”) under the “GL” shortcut, was resolved with this feature, as both flags now represent the proper ISO code.