### 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
}
		if (backbuffer_fbo != 0) {
			glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
			glReadBuffer(GL_COLOR_ATTACHMENT0);
			glBindFramebuffer(GL_DRAW_FRAMEBUFFER, backbuffer_fbo);
			if (scene_state.used_screen_texture) {
				glBlitFramebuffer(0, 0, size.x, size.y,
						0, 0, size.x, size.y,
						GL_COLOR_BUFFER_BIT, GL_NEAREST);
				glActiveTexture(GL_TEXTURE0 + config->max_texture_image_units - 5);
				glBindTexture(GL_TEXTURE_2D, backbuffer);
			}
			if (scene_state.used_depth_texture) {
				glBlitFramebuffer(0, 0, size.x, size.y,
						0, 0, size.x, size.y,
						GL_DEPTH_BUFFER_BIT, GL_NEAREST);
				glActiveTexture(GL_TEXTURE0 + config->max_texture_image_units - 6);
				glBindTexture(GL_TEXTURE_2D, backbuffer_depth);
			}
		}
		
		glBindFramebuffer(GL_FRAMEBUFFER, fbo);
	}
	RENDER_TIMESTAMP("Render 3D Transparent Pass");
	glEnable(GL_BLEND);
	
	RenderListParameters render_list_params_alpha(render_list[RENDER_LIST_ALPHA].elements.ptr(), render_list[RENDER_LIST_ALPHA].elements.size(), reverse_cull, spec_constant_base_flags, use_wireframe);
	_render_list_template<PASS_MODE_COLOR_TRANSPARENT>(&render_list_params_alpha, &render_data, 0, render_list[RENDER_LIST_ALPHA].elements.size(), true);
	if (!flip_y) {