### 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.
XrTime get_next_frame_time() { return frame_state.predictedDisplayTime + frame_state.predictedDisplayPeriod; }
	bool can_render() { return instance != XR_NULL_HANDLE && session != XR_NULL_HANDLE && running && view_pose_valid && frame_state.shouldRender; }
	Size2 get_recommended_target_size();
	XRPose::TrackingConfidence get_head_center(Transform3D &r_transform, Vector3 &r_linear_velocity, Vector3 &r_angular_velocity);
	bool get_view_transform(uint32_t p_view, Transform3D &r_transform);
	bool get_view_projection(uint32_t p_view, double p_z_near, double p_z_far, Projection &p_camera_matrix);
	bool process();
	void pre_render();
	bool pre_draw_viewport(RID p_render_target);
	XrSwapchain get_color_swapchain();
	RID get_color_texture();
	RID get_depth_texture();
	void post_draw_viewport(RID p_render_target);
	void end_frame();
	
	float get_display_refresh_rate() const;
	void set_display_refresh_rate(float p_refresh_rate);
	Array get_available_display_refresh_rates() const;
	
	double get_render_target_size_multiplier() const;
	void set_render_target_size_multiplier(double multiplier);
	
	bool is_foveation_supported() const;
	int get_foveation_level() const;
	void set_foveation_level(int p_foveation_level);
	bool get_foveation_dynamic() const;
	void set_foveation_dynamic(bool p_foveation_dynamic);