### 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)

vd.format = RD::DATA_FORMAT_R32G32B32A32_SFLOAT;
			vd.offset = 0;
			vd.location = RS::ARRAY_WEIGHTS;
			vd.stride = 0;
			descriptions.write[4] = vd;
			buffers.write[4] = mesh_storage->mesh_get_default_rd_buffer(RendererRD::MeshStorage::DEFAULT_RD_BUFFER_WEIGHTS);
		}
		
		ERR_FAIL_COND_V(base_offset != stride, 0); 
	}
	RD::VertexFormatID vertex_id = RD::get_singleton()->vertex_format_create(descriptions);
	ERR_FAIL_COND_V(vertex_id == RD::INVALID_ID, 0);
	PolygonBuffers pb;
	pb.vertex_buffer = RD::get_singleton()->vertex_buffer_create(polygon_buffer.size(), polygon_buffer);
	for (int i = 0; i < descriptions.size(); i++) {
		if (buffers[i] == RID()) { 
			buffers.write[i] = pb.vertex_buffer;
		}
	}
	pb.vertex_array = RD::get_singleton()->vertex_array_create(p_points.size(), vertex_id, buffers);
	if (p_indices.size()) {
		
		Vector<uint8_t> index_buffer;
		index_buffer.resize(p_indices.size() * sizeof(int32_t));
		{
			uint8_t *w = index_buffer.ptrw();
			memcpy(w, p_indices.ptr(), sizeof(int32_t) * p_indices.size());
		}
		pb.index_buffer = RD::get_singleton()->index_buffer_create(p_indices.size(), RD::INDEX_BUFFER_FORMAT_UINT32, index_buffer);
		pb.indices = RD::get_singleton()->index_array_create(pb.index_buffer, 0, p_indices.size());