### Godot version

master

### System information

Ubuntu

### Issue description

I think one of the recent changes wrapped the project converter in `#ifndef DISABLE_DEPRECATED` but missed the coresponding code in `main.cpp` (and potentially other places).
```
main/main.cpp: In static member function 'static bool Main::start()':
main/main.cpp:2551:33: error: 'ProjectConverter3To4' was not declared in this scope
 2551 |                 int exit_code = ProjectConverter3To4(converter_max_kb_file, converter_max_line_length).convert();
      |                                 ^~~~~~~~~~~~~~~~~~~~
main/main.cpp:2556:33: error: 'ProjectConverter3To4' was not declared in this scope
 2556 |                 int exit_code = ProjectConverter3To4(converter_max_kb_file, converter_max_line_length).validate_conversion();
```

### Steps to reproduce

for instance, try to compile with `deprecated = "no"` in your `custom.py`.

### Minimal reproduction project

n/a
/
	rendering_server->global_shader_parameters_clear();
	if (xr_server) {
		/
		/
		xr_server->set_primary_interface(Ref<XRInterface>());
	}
#ifdef TOOLS_ENABLED
	GDExtensionManager::get_singleton()->deinitialize_extensions(GDExtension::INITIALIZATION_LEVEL_EDITOR);
	uninitialize_modules(MODULE_INITIALIZATION_LEVEL_EDITOR);
	unregister_editor_types();
#endif
	ImageLoader::cleanup();
	GDExtensionManager::get_singleton()->deinitialize_extensions(GDExtension::INITIALIZATION_LEVEL_SCENE);
	uninitialize_modules(MODULE_INITIALIZATION_LEVEL_SCENE);
	unregister_platform_apis();
	unregister_driver_types();
	unregister_scene_types();
	finalize_theme_db();
	/
	finalize_navigation_server();
	finalize_physics();
	GDExtensionManager::get_singleton()->deinitialize_extensions(GDExtension::INITIALIZATION_LEVEL_SERVERS);
	uninitialize_modules(MODULE_INITIALIZATION_LEVEL_SERVERS);
	unregister_server_types();
	EngineDebugger::deinitialize();
	if (xr_server) {
		memdelete(xr_server);
	}
	if (audio_server) {