### Godot version

4.0 beta 10

### System information

Windows 10, Vulkan Renderer

### Issue description

In 2D scenes with sprites, when the sprite's `flip_h` and/or `flip_v` property is enabled, the normal map is flipped with the image, causing lighting to be reversed. While this does technically make sense, in a game where You have a bunch of sprites that flip and use normal maps, the only solution is to generate normal maps for both facing directions.
![image](https://user-images.githubusercontent.com/47702559/209426338-6257d66c-a965-4793-a7bb-5a635a136267.png)

Ultimately the fix is simple: Invert the red channel in normal maps on horizontally flipped sprites, and invert the green channel on vertically flipped sprites.

### Steps to reproduce

1) Create a Sprite2D
2) Add a Diffuse Texture and Normal Map 
3) Add a 2D Light to the scene
4) Enable `flip_h` and/or `flip_v` on the Sprite2D

### Minimal reproduction project

[Normal not flipped.zip](https://github.com/godotengine/godot/files/10298203/Normal.not.flipped.zip)

ShadowRenderPushConstant push_constant;
		for (int y = 0; y < 4; y++) {
			for (int x = 0; x < 4; x++) {
				push_constant.projection[y * 4 + x] = projection.columns[y][x];
			}
		}
		static const Vector2 directions[4] = { Vector2(1, 0), Vector2(0, 1), Vector2(-1, 0), Vector2(0, -1) };
		push_constant.direction[0] = directions[i].x;
		push_constant.direction[1] = directions[i].y;
		push_constant.z_far = p_far;
		push_constant.pad = 0;
		LightOccluderInstance *instance = p_occluders;
		while (instance) {
			OccluderPolygon *co = occluder_polygon_owner.get_or_null(instance->occluder);
			if (!co || co->index_array.is_null() || !(p_light_mask & instance->light_mask)) {
				instance = instance->next;
				continue;
			}
			_update_transform_2d_to_mat2x4(p_light_xform * instance->xform_cache, push_constant.modelview);
			RD::get_singleton()->draw_list_bind_render_pipeline(draw_list, shadow_render.render_pipelines[co->cull_mode]);
			RD::get_singleton()->draw_list_bind_vertex_array(draw_list, co->vertex_array);
			RD::get_singleton()->draw_list_bind_index_array(draw_list, co->index_array);
			RD::get_singleton()->draw_list_set_push_constant(draw_list, &push_constant, sizeof(ShadowRenderPushConstant));
			RD::get_singleton()->draw_list_draw(draw_list, true);
			instance = instance->next;
		}
		RD::get_singleton()->draw_list_end();
	}
}
void RendererCanvasRenderRD::light_update_directional_shadow(RID p_rid, int p_shadow_index, const Transform2D &p_light_xform, int p_light_mask, float p_cull_distance, const Rect2 &p_clip_rect, LightOccluderInstance *p_occluders) {