### 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.
BIND_ENUM_CONSTANT(HAND_JOINT_INDEX_DISTAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_INDEX_TIP);
	BIND_ENUM_CONSTANT(HAND_JOINT_MIDDLE_METACARPAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_MIDDLE_PROXIMAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_MIDDLE_INTERMEDIATE);
	BIND_ENUM_CONSTANT(HAND_JOINT_MIDDLE_DISTAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_MIDDLE_TIP);
	BIND_ENUM_CONSTANT(HAND_JOINT_RING_METACARPAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_RING_PROXIMAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_RING_INTERMEDIATE);
	BIND_ENUM_CONSTANT(HAND_JOINT_RING_DISTAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_RING_TIP);
	BIND_ENUM_CONSTANT(HAND_JOINT_LITTLE_METACARPAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_LITTLE_PROXIMAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_LITTLE_INTERMEDIATE);
	BIND_ENUM_CONSTANT(HAND_JOINT_LITTLE_DISTAL);
	BIND_ENUM_CONSTANT(HAND_JOINT_LITTLE_TIP);
	BIND_ENUM_CONSTANT(HAND_JOINT_MAX);
	BIND_BITFIELD_FLAG(HAND_JOINT_NONE);
	BIND_BITFIELD_FLAG(HAND_JOINT_ORIENTATION_VALID);
	BIND_BITFIELD_FLAG(HAND_JOINT_ORIENTATION_TRACKED);
	BIND_BITFIELD_FLAG(HAND_JOINT_POSITION_VALID);
	BIND_BITFIELD_FLAG(HAND_JOINT_POSITION_TRACKED);
	BIND_BITFIELD_FLAG(HAND_JOINT_LINEAR_VELOCITY_VALID);
	BIND_BITFIELD_FLAG(HAND_JOINT_ANGULAR_VELOCITY_VALID);
}
StringName OpenXRInterface::get_name() const {
	return StringName("OpenXR");
};
uint32_t OpenXRInterface::get_capabilities() const {