### 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.
HAND_JOINT_PALM = 0,
		HAND_JOINT_WRIST = 1,
		HAND_JOINT_THUMB_METACARPAL = 2,
		HAND_JOINT_THUMB_PROXIMAL = 3,
		HAND_JOINT_THUMB_DISTAL = 4,
		HAND_JOINT_THUMB_TIP = 5,
		HAND_JOINT_INDEX_METACARPAL = 6,
		HAND_JOINT_INDEX_PROXIMAL = 7,
		HAND_JOINT_INDEX_INTERMEDIATE = 8,
		HAND_JOINT_INDEX_DISTAL = 9,
		HAND_JOINT_INDEX_TIP = 10,
		HAND_JOINT_MIDDLE_METACARPAL = 11,
		HAND_JOINT_MIDDLE_PROXIMAL = 12,
		HAND_JOINT_MIDDLE_INTERMEDIATE = 13,
		HAND_JOINT_MIDDLE_DISTAL = 14,
		HAND_JOINT_MIDDLE_TIP = 15,
		HAND_JOINT_RING_METACARPAL = 16,
		HAND_JOINT_RING_PROXIMAL = 17,
		HAND_JOINT_RING_INTERMEDIATE = 18,
		HAND_JOINT_RING_DISTAL = 19,
		HAND_JOINT_RING_TIP = 20,
		HAND_JOINT_LITTLE_METACARPAL = 21,
		HAND_JOINT_LITTLE_PROXIMAL = 22,
		HAND_JOINT_LITTLE_INTERMEDIATE = 23,
		HAND_JOINT_LITTLE_DISTAL = 24,
		HAND_JOINT_LITTLE_TIP = 25,
		HAND_JOINT_MAX = 26,
	};
	enum HandJointFlags {