### 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.
ERR_FAIL_COND_V(session == XR_NULL_HANDLE, 0.0);
	Action *action = action_owner.get_or_null(p_action);
	ERR_FAIL_NULL_V(action, 0.0);
	Tracker *tracker = tracker_owner.get_or_null(p_tracker);
	ERR_FAIL_NULL_V(tracker, 0.0);
	if (!running) {
		return 0.0;
	}
	ERR_FAIL_COND_V(action->action_type != XR_ACTION_TYPE_FLOAT_INPUT, 0.0);
	XrActionStateGetInfo get_info = {
		XR_TYPE_ACTION_STATE_GET_INFO, 
		nullptr, 
		action->handle, 
		tracker->toplevel_path 
	};
	XrActionStateFloat result_state;
	result_state.type = XR_TYPE_ACTION_STATE_FLOAT,
	result_state.next = nullptr;
	XrResult result = xrGetActionStateFloat(session, &get_info, &result_state);
	if (XR_FAILED(result)) {
		print_line("OpenXR: couldn't get action float! [", get_error_string(result), "]");
		return 0.0;
	}
	return result_state.isActive ? result_state.currentState : 0.0;
}
Vector2 OpenXRAPI::get_action_vector2(RID p_action, RID p_tracker) {