### Godot version

4.0 beta 17

### System information

Windows 10

### Issue description

Setting the color attribute in ParticleProcessMaterial for GPUParticles2D does not work with compatibility renderer
(works with forward+)

### Steps to reproduce

Set renderer to compatibility
Create a GPUParticles2D
Add ParticleProcessMaterial and set Color attribute (creating a particle shader and setting the `COLOR` is the same)


### Minimal reproduction project

[Particle2DColor.zip](https://github.com/godotengine/godot/files/10678236/Particle2DColor.zip)

} else {
				if (material.is_null()) {
					if (ci->canvas_group->mode == RS::CANVAS_GROUP_MODE_CLIP_ONLY) {
						material = default_clip_children_material;
					} else {
						material = default_canvas_group_material;
					}
				}
			}
		}
		GLES3::CanvasShaderData *shader_data_cache = nullptr;
		if (material != state.canvas_instance_batches[state.current_batch_index].material) {
			_new_batch(batch_broken);
			GLES3::CanvasMaterialData *material_data = nullptr;
			if (material.is_valid()) {
				material_data = static_cast<GLES3::CanvasMaterialData *>(material_storage->material_get_data(material, RS::SHADER_CANVAS_ITEM));
			}
			shader_data_cache = nullptr;
			if (material_data) {
				if (material_data->shader_data->version.is_valid() && material_data->shader_data->valid) {
					shader_data_cache = material_data->shader_data;
				}
			}
			state.canvas_instance_batches[state.current_batch_index].material = material;
			state.canvas_instance_batches[state.current_batch_index].material_data = material_data;
		}
		GLES3::CanvasShaderData::BlendMode blend_mode = shader_data_cache ? shader_data_cache->blend_mode : GLES3::CanvasShaderData::BLEND_MODE_MIX;
		_record_item_commands(ci, p_to_render_target, p_canvas_transform_inverse, current_clip, blend_mode, p_lights, index, batch_broken, r_sdf_used);
	}
	if (index == 0) {