### Godot version

v4.2.dev3.official [013e8e3af]

### System information

Windows 11, Core i5-12400F, RX 6600

### Issue description

TileSet->Setup->Separation maybe should have "px" like rest?
![Screenshot 2023-08-21 162202](https://github.com/godotengine/godot/assets/962340/3c6b9a97-7520-4610-8153-7882cc9c303f)
I know this is pixels from testing it.

TileSet->Select is this Animation Separation "px" too? idk
![Screenshot 2023-08-21 162131](https://github.com/godotengine/godot/assets/962340/fcb580e3-9ff7-41d8-92d3-e585841d3803)
I tried setting up animation separation and got a not enough room error, so maybe not "px". idk


Thanks.


### Steps to reproduce

- open TileSet->Setup->Separation, note some have "px" and one doesn't
- open TileSet->Select, is this separation "px" too?


### Minimal reproduction project

n/a
if (!tile_set_atlas_source.is_valid()) {
		return false;
	}
	
	if (tiles.size() == 1) {
		const Vector2i &coords = tiles.front()->get().tile;
		const int &alternative = tiles.front()->get().alternative;
		if (alternative == 0) {
			Vector<String> components = String(p_name).split("/", true, 2);
			if (p_name == "atlas_coords") {
				r_ret = coords;
				return true;
			} else if (p_name == "size_in_atlas") {
				r_ret = tile_set_atlas_source->get_tile_size_in_atlas(coords);
				return true;
			}
		} else if (alternative > 0) {