### 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.
virtual Vector<BlitToScreen> post_draw_viewport(RID p_render_target, const Rect2 &p_screen_rect) override;
	virtual void end_frame() override;
	virtual bool is_passthrough_supported() override;
	virtual bool is_passthrough_enabled() override;
	virtual bool start_passthrough() override;
	virtual void stop_passthrough() override;
	
	virtual Array get_supported_environment_blend_modes() override;
	virtual XRInterface::EnvironmentBlendMode get_environment_blend_mode() const override;
	virtual bool set_environment_blend_mode(XRInterface::EnvironmentBlendMode mode) override;
	void on_state_ready();
	void on_state_visible();
	void on_state_focused();
	void on_state_stopping();
	void on_pose_recentered();
	void tracker_profile_changed(RID p_tracker, RID p_interaction_profile);
	
	enum Hand {
		HAND_LEFT,
		HAND_RIGHT,
		HAND_MAX,
	};
	enum HandMotionRange {
		HAND_MOTION_RANGE_UNOBSTRUCTED,
		HAND_MOTION_RANGE_CONFORM_TO_CONTROLLER,
		HAND_MOTION_RANGE_MAX
	};
	void set_motion_range(const Hand p_hand, const HandMotionRange p_motion_range);
	HandMotionRange get_motion_range(const Hand p_hand) const;
	enum HandJoints {