### 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
if (!is_inside_tree()) {
		tree_dirty = false;
		return;
	}
	if (tree->is_editing()) {
		return;
	}
	updating_tree = true;
	tree->clear();
	if (get_scene_node()) {
		_add_nodes(get_scene_node(), nullptr);
		last_hash = hash_djb2_one_64(0);
		_compute_hash(get_scene_node(), last_hash);
	}
	updating_tree = false;
	tree_dirty = false;
	if (!filter.strip_edges().is_empty()) {
		_update_filter(nullptr, p_scroll_to_selected);
	}
}
bool SceneTreeEditor::_update_filter(TreeItem *p_parent, bool p_scroll_to_selected) {