### 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.
Vector<BlitToScreen> blit_to_screen;
#ifndef ANDROID_ENABLED
	
	if (p_screen_rect != Rect2()) {
		BlitToScreen blit;
		blit.render_target = p_render_target;
		blit.multi_view.use_layer = true;
		blit.multi_view.layer = 0;
		blit.lens_distortion.apply = false;
		Size2 render_size = get_render_target_size();
		Rect2 dst_rect = p_screen_rect;
		float new_height = dst_rect.size.x * (render_size.y / render_size.x);
		if (new_height > dst_rect.size.y) {
			dst_rect.position.y = (0.5 * dst_rect.size.y) - (0.5 * new_height);
			dst_rect.size.y = new_height;
		} else {
			float new_width = dst_rect.size.y * (render_size.x / render_size.y);
			dst_rect.position.x = (0.5 * dst_rect.size.x) - (0.5 * new_width);
			dst_rect.size.x = new_width;
		}
		blit.dst_rect = dst_rect;
		blit_to_screen.push_back(blit);
	}
#endif
	if (openxr_api) {
		openxr_api->post_draw_viewport(p_render_target);
	}
	return blit_to_screen;
}
void OpenXRInterface::end_frame() {