I'm not sure what happended, I was working along in the editor and I noticed these two light and environment toggles where greyed out and I dont see how to turn them back on. Clicking the 3 dots just gives me the diasabled message and click them two greyed out icons does nothing.

If your current scene contains a DirectionalLight3D and a WorldEnvironment those buttons are greyed out.

If you don't have those in your then, your scene will get a "preview" directional light and environment, so working in your scene is not so dark. Those previews can be turned of with those buttons.

If you hover over those buttons there pops up an info telling you that.
Also on your screenshot the opened sun and environment menu says this.

Btw. in Godot you find such tooltips for most of the buttons. I love it. 🙂