### 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.
XrSystemId get_system_id() const { return system_id; };
	XrSession get_session() const { return session; };
	String get_runtime_name() const { return runtime_name; };
	String get_runtime_version() const { return runtime_version; };
	
	Transform3D transform_from_pose(const XrPosef &p_pose);
	
	XRPose::TrackingConfidence transform_from_location(const XrSpaceLocation &p_location, Transform3D &r_transform);
	XRPose::TrackingConfidence transform_from_location(const XrHandJointLocationEXT &p_location, Transform3D &r_transform);
	void parse_velocities(const XrSpaceVelocity &p_velocity, Vector3 &r_linear_velocity, Vector3 &r_angular_velocity);
	bool xr_result(XrResult result, const char *format, Array args = Array()) const;
	bool is_top_level_path_supported(const String &p_toplevel_path);
	bool is_interaction_profile_supported(const String &p_ip_path);
	bool interaction_profile_supports_io_path(const String &p_ip_path, const String &p_io_path);
	static bool openxr_is_enabled(bool p_check_run_in_editor = true);
	_FORCE_INLINE_ static OpenXRAPI *get_singleton() { return singleton; }