undefined-behavior in ot::RouterTable::IsAllocated(unsigned

undefined-behavior in ot::RouterTable::IsAllocated(unsigned: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). UndefinedBehaviorSanitizer: undefined-behavior in function ot::RouterTable::IsAllocated(unsigned char) const in file openthread/src/core/thread/router table.cpp