Using GridMaps tutorial has outdated information about Theme

[Tepitron]

Your Godot version: 4.3

**Issue description: Using GridMaps tutorial has outdated information regarding a GridMap-node and it's theme property. Under the title Using GridMap it states this accompanied by a picture: "Create a new scene and add a GridMap node. Add the mesh library by dragging the resource file from the FileSystem dock and dropping it in the 'Theme' property in the Inspector." The most recent version of godot has a Mesh Library and a Physics Material property instead. **

URL to the documentation page: https://docs.godotengine.org/en/stable/tutorials/3d/using_gridmaps.html

If you know how to fix the issue you are reporting please
consider opening a pull request. We provide a tutorial on
using git here: https://docs.godotengine.org/en/stable/community/contributing/pr_workflow.html,
writing documentation at https://docs.godotengine.org/en/stable/community/contributing/docs_writing_guidelines.html
and contributing to the class reference here: https://docs.godotengine.org/en/stable/community/contributing/updating_the_class_reference.html

[tetrapod00]

This is fixed in the latest (4.4+) version of the docs by #10640.

Since that change was a part of a larger update to the page which includes 4.4-only changes, and 4.4 is nearly released, it's not clear that we'll be going back and fixing older versions of the docs.