### 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)

_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used);
			item_count = 0;
			texture_storage->render_target_copy_to_back_buffer(p_to_render_target, back_buffer_rect, backbuffer_gen_mipmaps);
			backbuffer_copy = false;
			backbuffer_gen_mipmaps = false;
			material_screen_texture_cached = true; 
			material_screen_texture_mipmaps_cached = backbuffer_gen_mipmaps;
		}
		if (backbuffer_gen_mipmaps) {
			texture_storage->render_target_gen_back_buffer_mipmaps(p_to_render_target, back_buffer_rect);
			backbuffer_gen_mipmaps = false;
			material_screen_texture_mipmaps_cached = true;
		}
		items[item_count++] = ci;
		if (!ci->next || item_count == MAX_RENDER_ITEMS - 1) {
			if (update_skeletons) {
				mesh_storage->update_mesh_instances();
				update_skeletons = false;
			}
			_render_items(p_to_render_target, item_count, canvas_transform_inverse, p_light_list, r_sdf_used, false);
			
			item_count = 0;
		}
		ci = ci->next;
	}
	if (time_used) {
		RenderingServerDefault::redraw_request();
	}
}
RID RendererCanvasRenderRD::light_create() {