### Godot version

4.2.dev 80de898d721f952dac0b102d48bb73d6b02ee1e8

### System information

OpenXR

### Issue description

The Godot 3 OpenXR plugin supported obtaining boundary/guardian information in order to obtain play space logic. While we do have a function in the `XRInterface` in Godot 4 that is supposed to retrieve this information (`get_play_area`) it is not implemented on the Godot 4 `OpenXRInterface`.

This logic needs to be ported.

### Steps to reproduce

Call `get_play_area`, be amazed by it not returning data :P

### Minimal reproduction project

Any XR project.
emit_signal(SNAME("session_focussed"));
}
void OpenXRInterface::on_state_stopping() {
	emit_signal(SNAME("session_stopping"));
}
void OpenXRInterface::on_pose_recentered() {
	emit_signal(SNAME("pose_recentered"));
}
void OpenXRInterface::set_motion_range(const Hand p_hand, const HandMotionRange p_motion_range) {
	ERR_FAIL_INDEX(p_hand, HAND_MAX);
	ERR_FAIL_INDEX(p_motion_range, HAND_MOTION_RANGE_MAX);
	OpenXRHandTrackingExtension *hand_tracking_ext = OpenXRHandTrackingExtension::get_singleton();
	if (hand_tracking_ext && hand_tracking_ext->get_active()) {
		XrHandJointsMotionRangeEXT xr_motion_range;
		switch (p_motion_range) {
			case HAND_MOTION_RANGE_UNOBSTRUCTED:
				xr_motion_range = XR_HAND_JOINTS_MOTION_RANGE_UNOBSTRUCTED_EXT;
				break;
			case HAND_MOTION_RANGE_CONFORM_TO_CONTROLLER:
				xr_motion_range = XR_HAND_JOINTS_MOTION_RANGE_CONFORMING_TO_CONTROLLER_EXT;
				break;
			default:
				
				xr_motion_range = XR_HAND_JOINTS_MOTION_RANGE_CONFORMING_TO_CONTROLLER_EXT;
				break;
		}
		hand_tracking_ext->set_motion_range(OpenXRHandTrackingExtension::HandTrackedHands(p_hand), xr_motion_range);
	}
}
OpenXRInterface::HandMotionRange OpenXRInterface::get_motion_range(const Hand p_hand) const {