Support UNKNOWN for traffic light color/shape in TrafficSignalState

[HansRobo]

Description

Abstract

Previously, there was no way to specify UNKNOWN for color/shape in traffic light state other than specifying directly to APIs in C++.
In this pull-request, scenario_simulator_v2 started to suppot specifying them in the scenarios.

Background

To test the behavior of Autoware when the traffic light is in the UNKNOWN state.

References

https://github.com/autowarefoundation/autoware_msgs/blob/main/autoware_perception_msgs/msg/TrafficSignalElement.msg#L2

[github-actions]

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