### Godot version

4.2.dev 5ee983188de97ae027f9b9c1443438063f708a7e

### System information

Windows 10 - Compatibility renderer 

### Issue description

When running a VR project sky contribution is not working in the compatibility renderer:

![image](https://github.com/godotengine/godot/assets/1945449/7aa19569-95c8-41a2-913b-37b81f4728a7)

It is working fine in normal mode. Can be worked around by setting sky contribution to 0 and providing an ambient color.

### Steps to reproduce

Try any project with a proper sky setup in XR, just switch to compatibility renderer.

### Minimal reproduction project

I'll try and create an MVP soon that can be used without XR hardware, but for now this can be used:
https://github.com/BastiaanOlij/godot_openxr_demo
float phi = 2.0 * Math_PI * xi.x;
	float cos_theta = sqrt((1.0 - xi.y) / (1.0 + (roughness4 - 1.0) * xi.y));
	float sin_theta = sqrt(1.0 - cos_theta * cos_theta);
	
	Vector3 half_vector;
	half_vector.x = sin_theta * cos(phi);
	half_vector.y = sin_theta * sin(phi);
	half_vector.z = cos_theta;
	return half_vector;
}
float distribution_GGX(float NdotH, float roughness4) {