### 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)

BASE_UNIFORM_LOCATION = 0,
		GLOBAL_UNIFORM_LOCATION = 1,
		LIGHT_UNIFORM_LOCATION = 2,
		INSTANCE_UNIFORM_LOCATION = 3,
		MATERIAL_UNIFORM_LOCATION = 4,
	};
	struct StateBuffer {
		float canvas_transform[16];
		float screen_transform[16];
		float canvas_normal_transform[16];
		float canvas_modulate[4];
		float screen_pixel_size[2];
		float time;
		uint32_t use_pixel_snap;
		float sdf_to_tex[4];
		float sdf_to_screen[2];
		float screen_to_sdf[2];
		uint32_t directional_light_count;
		float tex_to_sdf;
		uint32_t pad1;