### 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)

RendererRD::TextureStorage *texture_storage = RendererRD::TextureStorage::get_singleton();
	RID fb = texture_storage->render_target_get_sdf_framebuffer(p_render_target);
	Rect2i rect = texture_storage->render_target_get_sdf_rect(p_render_target);
	Transform2D to_sdf;
	to_sdf.columns[0] *= rect.size.width;
	to_sdf.columns[1] *= rect.size.height;
	to_sdf.columns[2] = rect.position;
	Transform2D to_clip;
	to_clip.columns[0] *= 2.0;
	to_clip.columns[1] *= 2.0;
	to_clip.columns[2] = -Vector2(1.0, 1.0);
	to_clip = to_clip * to_sdf.affine_inverse();
	Vector<Color> cc;
	cc.push_back(Color(0, 0, 0, 0));
	RD::DrawListID draw_list = RD::get_singleton()->draw_list_begin(fb, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_READ, RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_DISCARD, cc);