### 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)

if (np->texture == RID()) {
					texpixel_size = Size2(1, 1);
					src_rect = Rect2(0, 0, 1, 1);
				} else {
					if (np->source != Rect2()) {
						src_rect = Rect2(np->source.position.x * texpixel_size.width, np->source.position.y * texpixel_size.height, np->source.size.x * texpixel_size.width, np->source.size.y * texpixel_size.height);
						state.instance_data_array[r_index].color_texture_pixel_size[0] = 1.0 / np->source.size.width;
						state.instance_data_array[r_index].color_texture_pixel_size[1] = 1.0 / np->source.size.height;
					} else {
						src_rect = Rect2(0, 0, 1, 1);
					}
				}
				state.instance_data_array[r_index].modulation[0] = np->color.r * base_color.r;
				state.instance_data_array[r_index].modulation[1] = np->color.g * base_color.g;
				state.instance_data_array[r_index].modulation[2] = np->color.b * base_color.b;
				state.instance_data_array[r_index].modulation[3] = np->color.a * base_color.a;
				state.instance_data_array[r_index].src_rect[0] = src_rect.position.x;
				state.instance_data_array[r_index].src_rect[1] = src_rect.position.y;
				state.instance_data_array[r_index].src_rect[2] = src_rect.size.width;
				state.instance_data_array[r_index].src_rect[3] = src_rect.size.height;
				state.instance_data_array[r_index].dst_rect[0] = dst_rect.position.x;
				state.instance_data_array[r_index].dst_rect[1] = dst_rect.position.y;
				state.instance_data_array[r_index].dst_rect[2] = dst_rect.size.width;
				state.instance_data_array[r_index].dst_rect[3] = dst_rect.size.height;
				state.instance_data_array[r_index].flags |= int(np->axis_x) << FLAGS_NINEPATCH_H_MODE_SHIFT;
				state.instance_data_array[r_index].flags |= int(np->axis_y) << FLAGS_NINEPATCH_V_MODE_SHIFT;
				if (np->draw_center) {
					state.instance_data_array[r_index].flags |= FLAGS_NINEPACH_DRAW_CENTER;
				}
				state.instance_data_array[r_index].ninepatch_margins[0] = np->margin[SIDE_LEFT];