### 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)

vwptr[i * 12 + 4] = lr[i * 2 + 1].y;
				vwptr[i * 12 + 5] = POLY_HEIGHT;
				vwptr[i * 12 + 6] = lr[i * 2 + 1].x;
				vwptr[i * 12 + 7] = lr[i * 2 + 1].y;
				vwptr[i * 12 + 8] = -POLY_HEIGHT;
				vwptr[i * 12 + 9] = lr[i * 2 + 0].x;
				vwptr[i * 12 + 10] = lr[i * 2 + 0].y;
				vwptr[i * 12 + 11] = -POLY_HEIGHT;
				iwptr[i * 6 + 0] = i * 4 + 0;
				iwptr[i * 6 + 1] = i * 4 + 1;
				iwptr[i * 6 + 2] = i * 4 + 2;
				iwptr[i * 6 + 3] = i * 4 + 2;
				iwptr[i * 6 + 4] = i * 4 + 3;
				iwptr[i * 6 + 5] = i * 4 + 0;
			}
		}
		
		if (oc->vertex_array.is_null()) {
			
			
			
			oc->vertex_buffer = RD::get_singleton()->vertex_buffer_create(lc * 6 * sizeof(real_t), geometry);
			Vector<RID> buffer;
			buffer.push_back(oc->vertex_buffer);
			oc->vertex_array = RD::get_singleton()->vertex_array_create(4 * lc / 2, shadow_render.vertex_format, buffer);
			
			oc->index_buffer = RD::get_singleton()->index_buffer_create(3 * lc, RD::INDEX_BUFFER_FORMAT_UINT16, indices);
			oc->index_array = RD::get_singleton()->index_array_create(oc->index_buffer, 0, 3 * lc);
		} else {