### Godot version

4.0 Beta 11

### System information

Windows 10 version 22H2, GeForce Game Ready Driver Version 528.02, GTX 1070

### Issue description

Since Beta 11 this error is given whenever a project is run in the forward+ renderer with OpenXR enabled. This error is not present with Beta 10 and previous versions.
![image](https://user-images.githubusercontent.com/38119387/212044209-1179b908-f010-47a1-ae53-bc2faadc30de.png)

I've tested with projects created in previous versions as well as the current version (Beta 11)

### Steps to reproduce

Create project, enable OpenXR in project settings, and run.

### Minimal reproduction project

N/A
OpenXRDisplayRefreshRateExtension *drrext = OpenXRDisplayRefreshRateExtension::get_singleton();
	if (drrext) {
		return drrext->get_refresh_rate();
	}
	return 0.0;
}
void OpenXRAPI::set_display_refresh_rate(float p_refresh_rate) {
	OpenXRDisplayRefreshRateExtension *drrext = OpenXRDisplayRefreshRateExtension::get_singleton();
	if (drrext != nullptr) {
		drrext->set_refresh_rate(p_refresh_rate);
	}
}
Array OpenXRAPI::get_available_display_refresh_rates() const {
	OpenXRDisplayRefreshRateExtension *drrext = OpenXRDisplayRefreshRateExtension::get_singleton();
	if (drrext != nullptr) {
		return drrext->get_available_refresh_rates();
	}
	return Array();
}
OpenXRAPI::OpenXRAPI() {