### Godot version

4.1 rc3

### 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

This™
![image](https://github.com/godotengine/godot/assets/2223172/cb33110f-a5b0-400a-951f-3fa425f05714)

It can still happen, but it's more difficult to trigger.

### Steps to reproduce

1. Create a new scene with a Control node
2. Add Theme to the Control
3. Open Theme Editor
4. Clear the `theme` property in Control
5. Save, with Theme Editor opened
6. Restart

### Minimal reproduction project

N/A
ERR_FAIL_COND(plugin_init_callback_count == MAX_INIT_CALLBACKS);
	plugin_init_callbacks[plugin_init_callback_count++] = p_callback;
}
EditorPluginInitializeCallback EditorNode::plugin_init_callbacks[EditorNode::MAX_INIT_CALLBACKS];
int EditorNode::build_callback_count = 0;
void EditorNode::add_build_callback(EditorBuildCallback p_callback) {
	ERR_FAIL_COND(build_callback_count == MAX_INIT_CALLBACKS);
	build_callbacks[build_callback_count++] = p_callback;
}
EditorBuildCallback EditorNode::build_callbacks[EditorNode::MAX_BUILD_CALLBACKS];
bool EditorNode::call_build() {
	bool builds_successful = true;
	for (int i = 0; i < build_callback_count && builds_successful; i++) {
		if (!build_callbacks[i]()) {
			ERR_PRINT("A Godot Engine build callback failed.");
			builds_successful = false;
		}
	}
	if (builds_successful && !editor_data.call_build()) {
		ERR_PRINT("An EditorPlugin build callback failed.");
		builds_successful = false;
	}
	return builds_successful;
}
void EditorNode::_inherit_imported(const String &p_action) {