### 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)

state_buffer.sdf_to_screen[0] = render_target_size.width / canvas_scale.x;
		state_buffer.sdf_to_screen[1] = render_target_size.height / canvas_scale.y;
		state_buffer.screen_to_sdf[0] = 1.0 / state_buffer.sdf_to_screen[0];
		state_buffer.screen_to_sdf[1] = 1.0 / state_buffer.sdf_to_screen[1];
		Rect2 sdf_rect = texture_storage->render_target_get_sdf_rect(p_to_render_target);
		Rect2 sdf_tex_rect(sdf_rect.position / canvas_scale, sdf_rect.size / canvas_scale);
		state_buffer.sdf_to_tex[0] = 1.0 / sdf_tex_rect.size.width;
		state_buffer.sdf_to_tex[1] = 1.0 / sdf_tex_rect.size.height;
		state_buffer.sdf_to_tex[2] = -sdf_tex_rect.position.x / sdf_tex_rect.size.width;
		state_buffer.sdf_to_tex[3] = -sdf_tex_rect.position.y / sdf_tex_rect.size.height;
		
		state_buffer.tex_to_sdf = 1.0 / ((canvas_scale.x + canvas_scale.y) * 0.5);
		RD::get_singleton()->buffer_update(state.canvas_state_buffer, 0, sizeof(State::Buffer), &state_buffer);
	}
	{ 
		default_filter = p_default_filter;
		default_repeat = p_default_repeat;
	}
	Item *ci = p_item_list;
	
	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;
	Item *canvas_group_owner = nullptr;
	bool update_skeletons = false;
	bool time_used = false;
	bool backbuffer_cleared = false;
	while (ci) {