### Godot version

4.1.1 stable

### System information

Windows 10

### Issue description

this is the default size loaded on startup 1024 which seems fine but it actually have loaded the default [2048] and ignored the size in project settings
![image](https://github.com/godotengine/godot/assets/53877170/c8c71de7-468a-487f-8e6c-dba1ce0f8fa5)

changing it now to any size will break it 
[2048]
![image](https://github.com/godotengine/godot/assets/53877170/3082ff09-b7d7-41f7-8fbb-813074a54135)

[512]
![image](https://github.com/godotengine/godot/assets/53877170/5ea4620f-52b5-4d0e-a5f5-747e777cd59d)


### Steps to reproduce

change 2d shadow atlas size in project settings while using compatibility renderer. 

### Minimal reproduction project

_
back_buffer_rect = Rect2();
						backbuffer_gen_mipmaps = md->shader_data->uses_screen_texture_mipmaps;
					} else if (!material_screen_texture_mipmaps_cached) {
						backbuffer_gen_mipmaps = md->shader_data->uses_screen_texture_mipmaps;
					}
				}
				if (md->shader_data->uses_sdf) {
					r_sdf_used = true;
				}
				if (md->shader_data->uses_time) {
					time_used = true;
				}
			}
		}
		if (ci->skeleton.is_valid()) {
			const Item::Command *c = ci->commands;
			while (c) {
				if (c->type == Item::Command::TYPE_MESH) {
					const Item::CommandMesh *cm = static_cast<const Item::CommandMesh *>(c);
					if (cm->mesh_instance.is_valid()) {
						mesh_storage->mesh_instance_check_for_update(cm->mesh_instance);
						mesh_storage->mesh_instance_set_canvas_item_transform(cm->mesh_instance, canvas_transform_inverse * ci->final_transform);
						update_skeletons = true;
					}
				}
				c = c->next;
			}
		}
		if (ci->canvas_group_owner != nullptr) {
			if (canvas_group_owner == nullptr) {