### 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)

GLuint vertex_array = 0;
		GLuint index_buffer = 0;
		int sdf_point_count = 0;
		int sdf_index_count = 0;
		GLuint sdf_vertex_buffer = 0;
		GLuint sdf_vertex_array = 0;
		GLuint sdf_index_buffer = 0;
		bool sdf_is_lines = false;
	};
	RID_Owner<OccluderPolygon> occluder_polygon_owner;
	void _update_shadow_atlas();
	struct {
		CanvasOcclusionShaderGLES3 shader;
		RID shader_version;
	} shadow_render;
	struct LightUniform {
		float matrix[8]; 
		float shadow_matrix[8]; 
		float color[4];
		uint8_t shadow_color[4];
		uint32_t flags; 
		float shadow_pixel_size;
		float height;
		float position[2];
		float shadow_z_far_inv;
		float shadow_y_ofs;
		float atlas_rect[4];
	};
public:
	enum {