### 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)

const uint8_t *vr = geometry.ptr();
			RD::get_singleton()->buffer_update(oc->vertex_buffer, 0, geometry.size(), vr);
			const uint8_t *ir = indices.ptr();
			RD::get_singleton()->buffer_update(oc->index_buffer, 0, indices.size(), ir);
		}
	}
	
	Vector<int> sdf_indices;
	if (p_points.size()) {
		if (p_closed) {
			sdf_indices = Geometry2D::triangulate_polygon(p_points);
			oc->sdf_is_lines = false;
		} else {
			int max = p_points.size();
			sdf_indices.resize(max * 2);
			int *iw = sdf_indices.ptrw();
			for (int i = 0; i < max; i++) {
				iw[i * 2 + 0] = i;
				iw[i * 2 + 1] = (i + 1) % max;
			}
			oc->sdf_is_lines = true;
		}
	}
	if (oc->sdf_index_count != sdf_indices.size() && oc->sdf_point_count != p_points.size() && oc->sdf_vertex_array.is_valid()) {
		RD::get_singleton()->free(oc->sdf_vertex_array);
		RD::get_singleton()->free(oc->sdf_vertex_buffer);
		RD::get_singleton()->free(oc->sdf_index_array);
		RD::get_singleton()->free(oc->sdf_index_buffer);
		oc->sdf_vertex_array = RID();
		oc->sdf_vertex_buffer = RID();