### 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)

MAX_RENDER_ITEMS = 256 * 1024,
		MAX_LIGHT_TEXTURES = 1024,
		MAX_LIGHTS_PER_ITEM = 16,
		DEFAULT_MAX_LIGHTS_PER_RENDER = 256,
	};
	
	
	
	struct CanvasLight {
		RID texture;
		struct {
			bool enabled = false;
			float z_far;
			float y_offset;
			Transform2D directional_xform;
		} shadow;
	};
	RID_Owner<CanvasLight> canvas_light_owner;
	struct OccluderPolygon {
		RS::CanvasOccluderPolygonCullMode cull_mode = RS::CANVAS_OCCLUDER_POLYGON_CULL_DISABLED;
		int line_point_count = 0;
		GLuint vertex_buffer = 0;