### 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)

OccluderPolygon occluder;
	occluder.line_point_count = 0;
	occluder.sdf_point_count = 0;
	occluder.sdf_index_count = 0;
	occluder.cull_mode = RS::CANVAS_OCCLUDER_POLYGON_CULL_DISABLED;
	return occluder_polygon_owner.make_rid(occluder);
}
void RendererCanvasRenderRD::occluder_polygon_set_shape(RID p_occluder, const Vector<Vector2> &p_points, bool p_closed) {
	OccluderPolygon *oc = occluder_polygon_owner.get_or_null(p_occluder);
	ERR_FAIL_COND(!oc);
	Vector<Vector2> lines;
	if (p_points.size()) {
		int lc = p_points.size() * 2;
		lines.resize(lc - (p_closed ? 0 : 2));
		{
			Vector2 *w = lines.ptrw();
			const Vector2 *r = p_points.ptr();
			int max = lc / 2;
			if (!p_closed) {
				max--;
			}
			for (int i = 0; i < max; i++) {
				Vector2 a = r[i];
				Vector2 b = r[(i + 1) % (lc / 2)];
				w[i * 2 + 0] = a;
				w[i * 2 + 1] = b;
			}
		}