### 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.
GDCLASS(OpenXRInterface, XRInterface);
private:
	OpenXRAPI *openxr_api = nullptr;
	bool initialized = false;
	XRInterface::TrackingStatus tracking_state;
	OpenXRFbPassthroughExtensionWrapper *passthrough_wrapper = nullptr;
	
	Ref<XRPositionalTracker> head;
	Transform3D head_transform;
	Vector3 head_linear_velocity;
	Vector3 head_angular_velocity;
	XRPose::TrackingConfidence head_confidence;
	Transform3D transform_for_view[2]; 
	void _load_action_map();
	struct Action { 
		String action_name; 
		OpenXRAction::ActionType action_type; 
		RID action_rid; 
	};
	struct ActionSet { 
		String action_set_name; 
		bool is_active; 
		Vector<Action *> actions; 
		RID action_set_rid; 
	};
	struct Tracker { 
		String tracker_name;