### 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)

RendererRD::MaterialStorage *material_storage = RendererRD::MaterialStorage::get_singleton();
	RendererRD::TextureStorage *texture_storage = RendererRD::TextureStorage::get_singleton();
	Item *current_clip = nullptr;
	Transform2D canvas_transform_inverse = p_canvas_transform_inverse;
	RID framebuffer;
	RID fb_uniform_set;
	bool clear = false;
	Vector<Color> clear_colors;
	if (p_to_backbuffer) {
		framebuffer = texture_storage->render_target_get_rd_backbuffer_framebuffer(p_to_render_target);
		fb_uniform_set = texture_storage->render_target_get_backbuffer_uniform_set(p_to_render_target);
	} else {
		framebuffer = texture_storage->render_target_get_rd_framebuffer(p_to_render_target);
		if (texture_storage->render_target_is_clear_requested(p_to_render_target)) {
			clear = true;
			clear_colors.push_back(texture_storage->render_target_get_clear_request_color(p_to_render_target));
			texture_storage->render_target_disable_clear_request(p_to_render_target);
		}
		
		fb_uniform_set = texture_storage->render_target_get_framebuffer_uniform_set(p_to_render_target);
	}
	if (fb_uniform_set.is_null() || !RD::get_singleton()->uniform_set_is_valid(fb_uniform_set)) {
		fb_uniform_set = _create_base_uniform_set(p_to_render_target, p_to_backbuffer);