Remove w/a with pinning libxml2 version (#2410)

This PR removes explicit pinning on libxml2 version `2.13.7` added in
scope of #2409.
The issue has been the new build published on conda-forge.

Author: antonwolfy

environments/build_conda_pkg.yml

@@ -4,4 +4,3 @@ channels:
 dependencies:
   - python=3.12 # conda-build does not support python 3.13
   - conda-build=25.3.2
-  - libxml2=2.13.7 # libs dependency issue in 2.14.0