### 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)

p_size = nearest_power_of_2_templated(p_size);
	if (p_size == state.shadow_texture_size) {
		return;
	}
	state.shadow_texture_size = p_size;
	if (state.shadow_fb.is_valid()) {
		RD::get_singleton()->free(state.shadow_texture);
		RD::get_singleton()->free(state.shadow_depth_texture);
		state.shadow_fb = RID();
		{
			
			RD::TextureFormat tf;
			tf.texture_type = RD::TEXTURE_TYPE_2D;
			tf.width = 4;
			tf.height = 4;
			tf.usage_bits = RD::TEXTURE_USAGE_SAMPLING_BIT;
			tf.format = RD::DATA_FORMAT_R32_SFLOAT;
			state.shadow_texture = RD::get_singleton()->texture_create(tf, RD::TextureView());
		}
	}
}
RendererCanvasRenderRD::~RendererCanvasRenderRD() {
	RendererRD::MaterialStorage *material_storage = RendererRD::MaterialStorage::get_singleton();
	
	material_storage->material_free(default_canvas_group_material);
	material_storage->shader_free(default_canvas_group_shader);
	material_storage->material_free(default_clip_children_material);
	material_storage->shader_free(default_clip_children_shader);