### 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)

GLES3::ParticlesStorage *particles_storage = GLES3::ParticlesStorage::get_singleton();
					GLES3::TextureStorage *texture_storage = GLES3::TextureStorage::get_singleton();
					const Item::CommandParticles *pt = static_cast<const Item::CommandParticles *>(c);
					RID particles = pt->particles;
					state.canvas_instance_batches[state.current_batch_index].tex = pt->texture;
					state.canvas_instance_batches[state.current_batch_index].shader_variant = CanvasShaderGLES3::MODE_INSTANCED;
					if (particles_storage->particles_has_collision(particles) && texture_storage->render_target_is_sdf_enabled(p_render_target)) {
						
						Transform2D xform = p_item->final_transform;
						GLuint sdf_texture = texture_storage->render_target_get_sdf_texture(p_render_target);
						Rect2 to_screen;
						{
							Rect2 sdf_rect = texture_storage->render_target_get_sdf_rect(p_render_target);
							to_screen.size = Vector2(1.0 / sdf_rect.size.width, 1.0 / sdf_rect.size.height);
							to_screen.position = -sdf_rect.position * to_screen.size;
						}
						particles_storage->particles_set_canvas_sdf_collision(pt->particles, true, xform, to_screen, sdf_texture);
					} else {
						particles_storage->particles_set_canvas_sdf_collision(pt->particles, false, Transform2D(), Rect2(), 0);
					}
					r_sdf_used |= particles_storage->particles_has_collision(particles);
				}
				state.canvas_instance_batches[state.current_batch_index].command = c;
				state.canvas_instance_batches[state.current_batch_index].command_type = c->type;
				_prepare_canvas_texture(state.canvas_instance_batches[state.current_batch_index].tex, state.canvas_instance_batches[state.current_batch_index].filter, state.canvas_instance_batches[state.current_batch_index].repeat, r_index, texpixel_size);
				state.instance_data_array[r_index].modulation[0] = base_color.r * modulate.r;
				state.instance_data_array[r_index].modulation[1] = base_color.g * modulate.g;
				state.instance_data_array[r_index].modulation[2] = base_color.b * modulate.b;
				state.instance_data_array[r_index].modulation[3] = base_color.a * modulate.a;
				for (int j = 0; j < 4; j++) {