feat: Only load plugins if builtin python is available.

[melund]

This pull request introduces several changes to improve Python integration and update dependencies in the project. The most important changes include adding conditional switch for Python availability, defining and using the ANYBODY_BUILTIN_PYTHON_AVAILABLE macro, and updating various dependencies in the pixi.toml file.

Python Integration:

• Added conditional compilation for AnyGUIPlugin definitions in BM_Plugin.any and ANSUR_Plugin.any based on the ANYBODY_BUILTIN_PYTHON_AVAILABLE macro. [1] [2] [3] [4]
• Defined the ANYBODY_BUILTIN_PYTHON_AVAILABLE macro and added a message to notify users if Python is not available. [1] [2]

Dependency Updates:

• Updated Python and various package dependencies in the pixi.toml file to newer versions. [1] [2]

[bkje14]

Very nice addition, I ran into this issue before without knowing how to fix it :D