### 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
#include "scene_tree_editor.h"
#include "core/config/project_settings.h"
#include "core/object/message_queue.h"
#include "editor/editor_file_system.h"
#include "editor/editor_node.h"
#include "editor/editor_scale.h"
#include "editor/editor_settings.h"
#include "editor/editor_undo_redo_manager.h"
#include "editor/node_dock.h"
#include "editor/plugins/animation_player_editor_plugin.h"
#include "editor/plugins/canvas_item_editor_plugin.h"
#include "editor/plugins/script_editor_plugin.h"
#include "scene/gui/label.h"
#include "scene/gui/tab_container.h"
#include "scene/gui/texture_rect.h"
#include "scene/main/window.h"
#include "scene/resources/packed_scene.h"
Node *SceneTreeEditor::get_scene_node() {