### 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)

code = p_code;
	valid = false;
	ubo_size = 0;
	uniforms.clear();
	uses_screen_texture = false;
	uses_screen_texture_mipmaps = false;
	uses_sdf = false;
	uses_time = false;
	if (code.is_empty()) {
		return; 
	}
	ShaderCompiler::GeneratedCode gen_code;
	int blend_mode = BLEND_MODE_MIX;
	ShaderCompiler::IdentifierActions actions;
	actions.entry_point_stages["vertex"] = ShaderCompiler::STAGE_VERTEX;
	actions.entry_point_stages["fragment"] = ShaderCompiler::STAGE_FRAGMENT;
	actions.entry_point_stages["light"] = ShaderCompiler::STAGE_FRAGMENT;
	actions.render_mode_values["blend_add"] = Pair<int *, int>(&blend_mode, BLEND_MODE_ADD);
	actions.render_mode_values["blend_mix"] = Pair<int *, int>(&blend_mode, BLEND_MODE_MIX);
	actions.render_mode_values["blend_sub"] = Pair<int *, int>(&blend_mode, BLEND_MODE_SUB);
	actions.render_mode_values["blend_mul"] = Pair<int *, int>(&blend_mode, BLEND_MODE_MUL);
	actions.render_mode_values["blend_premul_alpha"] = Pair<int *, int>(&blend_mode, BLEND_MODE_PMALPHA);
	actions.render_mode_values["blend_disabled"] = Pair<int *, int>(&blend_mode, BLEND_MODE_DISABLED);
	actions.usage_flag_pointers["SCREEN_TEXTURE"] = &uses_screen_texture;
	actions.usage_flag_pointers["texture_sdf"] = &uses_sdf;