### 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
glFrontFace(GL_CCW);
	}
	if (rb.is_valid()) {
		_render_buffers_debug_draw(rb, p_shadow_atlas, fbo);
	}
	glDisable(GL_BLEND);
	_render_post_processing(&render_data);
	texture_storage->render_target_disable_clear_request(rb->render_target);
	glActiveTexture(GL_TEXTURE0);
}
void RasterizerSceneGLES3::_render_post_processing(const RenderDataGLES3 *p_render_data) {
	GLES3::TextureStorage *texture_storage = GLES3::TextureStorage::get_singleton();
	Ref<RenderSceneBuffersGLES3> rb = p_render_data->render_buffers;
	ERR_FAIL_COND(rb.is_null());
	RID render_target = rb->get_render_target();
	Size2i internal_size = rb->get_internal_size();
	Size2i target_size = rb->get_target_size();
	uint32_t view_count = rb->get_view_count();
	
	bool msaa3d_needs_resolve = rb->get_msaa_needs_resolve();
	GLuint fbo_msaa_3d = rb->get_msaa3d_fbo();
	GLuint fbo_int = rb->get_internal_fbo();
	GLuint fbo_rt = texture_storage->render_target_get_fbo(render_target); 
	if (view_count == 1) {
		
		if (fbo_msaa_3d != 0 && msaa3d_needs_resolve) {
			
			glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo_msaa_3d);
			if (fbo_int != 0) {