### 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 "scene/gui/spin_box.h"
#include "scene/gui/split_container.h"
#include "scene/gui/subviewport_container.h"
#include "scene/gui/tab_bar.h"
#include "scene/gui/tab_container.h"
#include "scene/gui/text_edit.h"
#include "scene/gui/texture_button.h"
#include "scene/gui/texture_progress_bar.h"
#include "scene/gui/texture_rect.h"
#include "scene/gui/tree.h"
#include "scene/gui/video_stream_player.h"
#include "scene/main/canvas_item.h"
#include "scene/main/canvas_layer.h"
#include "scene/main/http_request.h"
#include "scene/main/instance_placeholder.h"
#include "scene/main/missing_node.h"
#include "scene/main/multiplayer_api.h"
#include "scene/main/resource_preloader.h"
#include "scene/main/scene_tree.h"
#include "scene/main/timer.h"
#include "scene/main/viewport.h"
#include "scene/main/window.h"
#include "scene/resources/animation_library.h"
#include "scene/resources/audio_stream_polyphonic.h"
#include "scene/resources/audio_stream_wav.h"
#include "scene/resources/bit_map.h"
#include "scene/resources/bone_map.h"
#include "scene/resources/box_shape_3d.h"
#include "scene/resources/camera_attributes.h"
#include "scene/resources/capsule_shape_2d.h"