### 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)

BLEND_MODE_MIX,
			BLEND_MODE_ADD,
			BLEND_MODE_SUB,
			BLEND_MODE_MUL,
			BLEND_MODE_PMALPHA,
			BLEND_MODE_DISABLED,
		};
		bool valid = false;
		RID version;
		PipelineVariants pipeline_variants;
		Vector<ShaderCompiler::GeneratedCode::Texture> texture_uniforms;
		Vector<uint32_t> ubo_offsets;
		uint32_t ubo_size = 0;
		String code;
		bool uses_screen_texture = false;
		bool uses_screen_texture_mipmaps = false;
		bool uses_sdf = false;
		bool uses_time = false;
		virtual void set_code(const String &p_Code);
		virtual bool is_animated() const;
		virtual bool casts_shadows() const;
		virtual RS::ShaderNativeSourceCode get_native_source_code() const;
		CanvasShaderData() {}