### 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)

actions.usage_flag_pointers["TIME"] = &uses_time;
	actions.uniforms = &uniforms;
	RendererCanvasRenderRD *canvas_singleton = static_cast<RendererCanvasRenderRD *>(RendererCanvasRender::singleton);
	Error err = canvas_singleton->shader.compiler.compile(RS::SHADER_CANVAS_ITEM, code, &actions, path, gen_code);
	ERR_FAIL_COND_MSG(err != OK, "Shader compilation failed.");
	uses_screen_texture_mipmaps = gen_code.uses_screen_texture_mipmaps;
	if (version.is_null()) {
		version = canvas_singleton->shader.canvas_shader.version_create();
	}
#if 0
	print_line("**compiling shader:");
	print_line("**defines:\n");
	for (int i = 0; i < gen_code.defines.size(); i++) {
		print_line(gen_code.defines[i]);
	}
	HashMap<String, String>::Iterator el = gen_code.code.begin();
	while (el) {
		print_line("\n**code " + el->key + ":\n" + el->value);
		++el;
	}
	print_line("\n**uniforms:\n" + gen_code.uniforms);
	print_line("\n**vertex_globals:\n" + gen_code.stage_globals[ShaderCompiler::STAGE_VERTEX]);
	print_line("\n**fragment_globals:\n" + gen_code.stage_globals[ShaderCompiler::STAGE_FRAGMENT]);
#endif
	canvas_singleton->shader.canvas_shader.version_set_code(version, gen_code.code, gen_code.uniforms, gen_code.stage_globals[ShaderCompiler::STAGE_VERTEX], gen_code.stage_globals[ShaderCompiler::STAGE_FRAGMENT], gen_code.defines);
	ERR_FAIL_COND(!canvas_singleton->shader.canvas_shader.version_is_valid(version));
	ubo_size = gen_code.uniform_total_size;
	ubo_offsets = gen_code.uniform_offsets;
	texture_uniforms = gen_code.texture_uniforms;