### 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
glDepthMask(GL_FALSE);
		glDisable(GL_DEPTH_TEST);
		glDisable(GL_SCISSOR_TEST);
		glCullFace(GL_BACK);
		glEnable(GL_CULL_FACE);
		scene_state.cull_mode = GLES3::SceneShaderData::CULL_BACK;
		for (int i = 0; i < 6; i++) {
			Basis local_view = Basis::looking_at(view_normals[i], view_up[i]);
			material_storage->shaders.sky_shader.version_set_uniform(SkyShaderGLES3::ORIENTATION, local_view, shader_data->version, SkyShaderGLES3::MODE_CUBEMAP);
			glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, sky->raw_radiance, 0);
			glDrawArrays(GL_TRIANGLES, 0, 3);
		}
		if (update_single_frame) {
			for (int i = 0; i < max_processing_layer; i++) {
				_filter_sky_radiance(sky, i);
			}
		} else {
			_filter_sky_radiance(sky, 0); 
		}
		sky->processing_layer = 1;
		sky->baked_exposure = p_luminance_multiplier;
		sky->reflection_dirty = false;
	} else {
		if (sky_mode == RS::SKY_MODE_INCREMENTAL && sky->processing_layer < max_processing_layer) {
			_filter_sky_radiance(sky, sky->processing_layer);
			sky->processing_layer++;
		}
	}
}
Vector3 importance_sample_GGX(Vector2 xi, float roughness4) {