### 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)

if (state.shadow_fb == RID()) {
		
		RD::get_singleton()->free(state.shadow_texture); 
		Vector<RID> fb_textures;
		{ 
			RD::TextureFormat tf;
			tf.texture_type = RD::TEXTURE_TYPE_2D;
			tf.width = state.shadow_texture_size;
			tf.height = state.max_lights_per_render * 2;
			tf.usage_bits = RD::TEXTURE_USAGE_COLOR_ATTACHMENT_BIT | RD::TEXTURE_USAGE_SAMPLING_BIT;
			tf.format = RD::DATA_FORMAT_R32_SFLOAT;
			state.shadow_texture = RD::get_singleton()->texture_create(tf, RD::TextureView());
			fb_textures.push_back(state.shadow_texture);
		}
		{
			RD::TextureFormat tf;
			tf.texture_type = RD::TEXTURE_TYPE_2D;
			tf.width = state.shadow_texture_size;
			tf.height = state.max_lights_per_render * 2;
			tf.usage_bits = RD::TEXTURE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
			tf.format = RD::DATA_FORMAT_D32_SFLOAT;
			
			state.shadow_depth_texture = RD::get_singleton()->texture_create(tf, RD::TextureView());
			fb_textures.push_back(state.shadow_depth_texture);
		}
		state.shadow_fb = RD::get_singleton()->framebuffer_create(fb_textures);
	}
}
void RendererCanvasRenderRD::light_update_shadow(RID p_rid, int p_shadow_index, const Transform2D &p_light_xform, int p_light_mask, float p_near, float p_far, LightOccluderInstance *p_occluders) {