* Adds both a preview sun and preview environment to the 3D editor.
* They are valid as long as a DirectionalLight3D and WorldEnvironment are not in the scene.
* If any is added to the scene, the respective preview is disabled.
* Changed WorldEnvironment to better handle multiple node versions.
* Added a function in SceneTree to get the first node in a group.
* Fixed button minimum size to also consider font height if no text is there, this broke with the TextSever PR.