### 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
tree->set_filter(p_filter);
}
void SceneTreeDialog::_bind_methods() {
	ClassDB::bind_method("_cancel", &SceneTreeDialog::_cancel);
	ADD_SIGNAL(MethodInfo("selected", PropertyInfo(Variant::NODE_PATH, "path")));
}
SceneTreeDialog::SceneTreeDialog() {
	set_title(TTR("Select a Node"));
	VBoxContainer *vbc = memnew(VBoxContainer);
	add_child(vbc);
	filter = memnew(LineEdit);
	filter->set_h_size_flags(Control::SIZE_EXPAND_FILL);
	filter->set_placeholder(TTR("Filter Nodes"));
	filter->set_clear_button_enabled(true);
	filter->add_theme_constant_override("minimum_character_width", 0);
	filter->connect("text_changed", callable_mp(this, &SceneTreeDialog::_filter_changed));
	vbc->add_child(filter);
	tree = memnew(SceneTreeEditor(false, false, true));
	tree->set_v_size_flags(Control::SIZE_EXPAND_FILL);
	tree->get_scene_tree()->connect("item_activated", callable_mp(this, &SceneTreeDialog::_select));
	vbc->add_child(tree);
	// Disable the OK button when no node is selected.
	get_ok_button()->set_disabled(!tree->get_selected());
	tree->connect("node_selected", callable_mp(this, &SceneTreeDialog::_selected_changed));
}
SceneTreeDialog::~SceneTreeDialog() {
}