### Godot version

4.0.2.stable (7a0977c)

### System information

Ubuntu 22.04, x86_64, LLVM

### Issue description

When performing a dedicated server export with:
- a `ShaderMaterial` (a `canvas_item` shader used on a `Panel` in the example below)
- a build with `disable_3d=yes`

the resulting export gives the following error when run:
```
ERROR: Cannot get class 'PlaceholderMaterial'.
   at: instantiate (core/object/class_db.cpp:326)
ERROR: res://main.tscn:Resource of unrecognized type in file: PlaceholderMaterial.
   at: load (core/io/resource_format_binary.cpp:778)
ERROR: Failed loading resource: res://.godot/exported/206107301/export-3070c538c03ee49b7677ff960a3f5195-main.scn. Make sure resources have been imported by opening the project in the editor at least once.
   at: _load (core/io/resource_loader.cpp:223)
ERROR: Failed loading scene: res://main.tscn
   at: start (main/main.cpp:2965)
```

I would expect things to work here without an error - there's no 3D in use here and a normal export with the same build does run as expected.

### Steps to reproduce

1. Build godot with `disable_3d=yes`.
2. Create a new project, and add a `Panel` node.
3. Add a `canvas_item` shader as the material for the `Panel` node.
4. Perform a dedicated server export using the build from step 1.
5. Run the exported binary and observe the error.

### Minimal reproduction project

[DedicatedServer2DTest.zip](https://github.com/godotengine/godot/files/11597444/DedicatedServer2DTest.zip)

#include "register_scene_types.h"
#include "core/config/project_settings.h"
#include "core/extension/gdextension_manager.h"
#include "core/object/class_db.h"
#include "core/os/os.h"
#include "scene/2d/animated_sprite_2d.h"
#include "scene/2d/area_2d.h"
#include "scene/2d/audio_listener_2d.h"
#include "scene/2d/audio_stream_player_2d.h"
#include "scene/2d/back_buffer_copy.h"
#include "scene/2d/camera_2d.h"
#include "scene/2d/canvas_group.h"
#include "scene/2d/canvas_modulate.h"
#include "scene/2d/collision_polygon_2d.h"
#include "scene/2d/collision_shape_2d.h"
#include "scene/2d/cpu_particles_2d.h"
#include "scene/2d/gpu_particles_2d.h"
#include "scene/2d/joint_2d.h"
#include "scene/2d/light_2d.h"
#include "scene/2d/light_occluder_2d.h"
#include "scene/2d/line_2d.h"
#include "scene/2d/marker_2d.h"
#include "scene/2d/mesh_instance_2d.h"
#include "scene/2d/multimesh_instance_2d.h"
#include "scene/2d/navigation_agent_2d.h"
#include "scene/2d/navigation_link_2d.h"
#include "scene/2d/navigation_obstacle_2d.h"
#include "scene/2d/navigation_region_2d.h"