bug fix, to ensure that the timestamp comparison works with rosbags.

[dev10110]

To get the latest transform, originally the code was

if (timestamp == rclcpp::Time(0) {
    ...
}

However, when using rclcpp::Time(0), it automatically sets the clock_type to RCL_SYSTEM_TIME but if we are using a rosbag, the messages are coming on clock_type RCL_ROS_TIME this means that the equality check fails. so instead, we explicitly construct a time that has the same clocktype as the timestamp