### 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)

w[i * 2 + 1] = b;
			}
		}
	}
	if (oc->line_point_count != lines.size() && oc->vertex_array != 0) {
		glDeleteVertexArrays(1, &oc->vertex_array);
		glDeleteBuffers(1, &oc->vertex_buffer);
		glDeleteBuffers(1, &oc->index_buffer);
		oc->vertex_array = 0;
		oc->vertex_buffer = 0;
		oc->index_buffer = 0;
	}
	if (lines.size()) {
		Vector<uint8_t> geometry;
		Vector<uint8_t> indices;
		int lc = lines.size();
		geometry.resize(lc * 6 * sizeof(float));
		indices.resize(lc * 3 * sizeof(uint16_t));
		{
			uint8_t *vw = geometry.ptrw();
			float *vwptr = reinterpret_cast<float *>(vw);
			uint8_t *iw = indices.ptrw();
			uint16_t *iwptr = (uint16_t *)iw;
			const Vector2 *lr = lines.ptr();
			const int POLY_HEIGHT = 16384;
			for (int i = 0; i < lc / 2; i++) {
				vwptr[i * 12 + 0] = lr[i * 2 + 0].x;
				vwptr[i * 12 + 1] = lr[i * 2 + 0].y;
				vwptr[i * 12 + 2] = POLY_HEIGHT;
				vwptr[i * 12 + 3] = lr[i * 2 + 1].x;