### 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
ERR_FAIL_COND(p_id < 0);
	if (source_id == p_id) {
		return;
	}
	ERR_FAIL_COND_MSG(tile_set->has_source(p_id), vformat("Cannot change TileSet Atlas Source ID. Another source exists with id %d.", p_id));
	int previous_source = source_id;
	source_id = p_id; 
	tile_set->set_source_id(previous_source, p_id);
	emit_signal(SNAME("changed"), "id");
}
int TileSetAtlasSourceEditor::TileSetAtlasSourceProxyObject::get_id() const {