### 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)

glBindBuffer(GL_UNIFORM_BUFFER, 0);
	}
	glActiveTexture(GL_TEXTURE0 + GLES3::Config::get_singleton()->max_texture_image_units - 5);
	glBindTexture(GL_TEXTURE_2D, texture_storage->render_target_get_sdf_texture(p_to_render_target));
	{
		state.default_filter = p_default_filter;
		state.default_repeat = p_default_repeat;
	}
	Size2 render_target_size = texture_storage->render_target_get_size(p_to_render_target);
	glViewport(0, 0, render_target_size.x, render_target_size.y);
	r_sdf_used = false;
	int item_count = 0;
	bool backbuffer_cleared = false;
	bool time_used = false;
	bool material_screen_texture_cached = false;
	bool material_screen_texture_mipmaps_cached = false;
	Rect2 back_buffer_rect;
	bool backbuffer_copy = false;
	bool backbuffer_gen_mipmaps = false;
	bool update_skeletons = false;
	Item *ci = p_item_list;
	Item *canvas_group_owner = nullptr;
	uint32_t starting_index = 0;
	while (ci) {
		if (ci->copy_back_buffer && canvas_group_owner == nullptr) {
			backbuffer_copy = true;
			if (ci->copy_back_buffer->full) {
				back_buffer_rect = Rect2();
			} else {
				back_buffer_rect = ci->copy_back_buffer->rect;