### 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.
ERR_FAIL_INDEX_V(p_hand, HAND_MAX, HAND_MOTION_RANGE_MAX);
	OpenXRHandTrackingExtension *hand_tracking_ext = OpenXRHandTrackingExtension::get_singleton();
	if (hand_tracking_ext && hand_tracking_ext->get_active()) {
		XrHandJointsMotionRangeEXT xr_motion_range = hand_tracking_ext->get_motion_range(OpenXRHandTrackingExtension::HandTrackedHands(p_hand));
		switch (xr_motion_range) {
			case XR_HAND_JOINTS_MOTION_RANGE_UNOBSTRUCTED_EXT:
				return HAND_MOTION_RANGE_UNOBSTRUCTED;
			case XR_HAND_JOINTS_MOTION_RANGE_CONFORMING_TO_CONTROLLER_EXT:
				return HAND_MOTION_RANGE_CONFORM_TO_CONTROLLER;
			default:
				ERR_FAIL_V_MSG(HAND_MOTION_RANGE_MAX, "Unknown motion range returned by OpenXR");
		}
	}
	return HAND_MOTION_RANGE_MAX;
}
BitField<OpenXRInterface::HandJointFlags> OpenXRInterface::get_hand_joint_flags(Hand p_hand, HandJoints p_joint) const {