### Godot version

4.1

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description


https://github.com/godotengine/godot/assets/2223172/3c8ee782-9d5f-42e3-a70f-d2aa59a233dd

We correctly clamp the size to 16x16 everywhere except here (probably).

### Steps to reproduce

1. Add a class with custom icon, e.g.
```GDScript
@icon("res://icon.svg")
extends Node
class_name Icon
```
2. Add it to scene
3. Open Script Editor and drag the node to script editor

### Minimal reproduction project

N/A
NodePath np = item->get_metadata(0);
	Node *n = get_node(np);
	if (!n) {
		return;
	}
	Dictionary d = p_data;
	if (String(d["type"]) == "nodes") {
		Array nodes = d["nodes"];
		emit_signal(SNAME("nodes_rearranged"), nodes, np, section);
	}
	if (String(d["type"]) == "files") {
		Vector<String> files = d["files"];
		String ftype = EditorFileSystem::get_singleton()->get_file_type(files[0]);
		if (_is_script_type(ftype)) {
			emit_signal(SNAME("script_dropped"), files[0], np);
		} else {
			emit_signal(SNAME("files_dropped"), files, np, section);
		}
	}
	if (String(d["type"]) == "script_list_element") {
		ScriptEditorBase *se = Object::cast_to<ScriptEditorBase>(d["script_list_element"]);
		if (se) {
			String sp = se->get_edited_resource()->get_path();
			if (_is_script_type(EditorFileSystem::get_singleton()->get_file_type(sp))) {
				emit_signal(SNAME("script_dropped"), sp, np);
			}
		}
	}
}
void SceneTreeEditor::_empty_clicked(const Vector2 &p_pos, MouseButton p_button) {