Remove usages of pkg_resources

`pkg_resources` is deprecated and will be removed soon. 

https://setuptools.pypa.io/en/latest/pkg_resources.html

> The pkg_resources package is slated for removal as early as 2025-11-30. Refrain from using this package or pin to Setuptools<81.

Migrating to the `importlib` replacements will ensure that downstream consumers of the package will be able to upgrade without issue.