### 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)

uint32_t current_buffer_index = 0;
		uint32_t current_batch_index = 0;
		InstanceData *instance_data_array = nullptr;
		LightUniform *light_uniforms = nullptr;
		GLuint shadow_texture = 0;
		GLuint shadow_depth_buffer = 0;
		GLuint shadow_fb = 0;
		int shadow_texture_size = 2048;
		bool using_directional_lights = false;
		RID current_tex;
		RS::CanvasItemTextureFilter current_filter_mode = RS::CANVAS_ITEM_TEXTURE_FILTER_MAX;
		RS::CanvasItemTextureRepeat current_repeat_mode = RS::CANVAS_ITEM_TEXTURE_REPEAT_MAX;
		bool transparent_render_target = false;
		double time = 0.0;
		RS::CanvasItemTextureFilter default_filter = RS::CANVAS_ITEM_TEXTURE_FILTER_DEFAULT;
		RS::CanvasItemTextureRepeat default_repeat = RS::CANVAS_ITEM_TEXTURE_REPEAT_DEFAULT;
	} state;
	Item *items[MAX_RENDER_ITEMS];
	RID default_canvas_texture;
	RID default_canvas_group_material;
	RID default_canvas_group_shader;
	RID default_clip_children_material;
	RID default_clip_children_shader;
	typedef void Texture;
	void canvas_begin(RID p_to_render_target, bool p_to_backbuffer);
	
	void draw_lens_distortion_rect(const Rect2 &p_rect, float p_k1, float p_k2, const Vector2 &p_eye_center, float p_oversample);
	void reset_canvas();
	RID light_create() override;
	void light_set_texture(RID p_rid, RID p_texture) override;