### 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)

material_storage->shader_initialize(default_clip_children_shader);
		material_storage->shader_set_code(default_clip_children_shader, R"(
// Default clip children shader.
shader_type canvas_item;
void fragment() {
	vec4 c = textureLod(SCREEN_TEXTURE, SCREEN_UV, 0.0);
	COLOR.rgb = c.rgb;
}
)");
		default_clip_children_material = material_storage->material_allocate();
		material_storage->material_initialize(default_clip_children_material);
		material_storage->material_set_shader(default_clip_children_material, default_clip_children_shader);
	}
	static_assert(sizeof(PushConstant) == 128);
}
bool RendererCanvasRenderRD::free(RID p_rid) {
	if (canvas_light_owner.owns(p_rid)) {
		CanvasLight *cl = canvas_light_owner.get_or_null(p_rid);
		ERR_FAIL_COND_V(!cl, false);
		light_set_use_shadow(p_rid, false);
		canvas_light_owner.free(p_rid);
	} else if (occluder_polygon_owner.owns(p_rid)) {
		occluder_polygon_set_shape(p_rid, Vector<Vector2>(), false);
		occluder_polygon_owner.free(p_rid);
	} else {
		return false;
	}
	return true;
}
void RendererCanvasRenderRD::set_shadow_texture_size(int p_size) {