OPENTHREAD_CONFIG_CHILD_SUPERVISION_CHECK_TIMEOUT macro

@def OPENTHREAD_CONFIG_CHILD_SUPERVISION_CHECK_TIMEOUT The default supervision check timeout interval (in seconds) used by a device in child state. Set to zero to disable the supervision check process on the child. The check timeout interval can be changed using `otChildSupervisionSetCheckTimeout()`. If the sleepy child does not hear from its parent within the specified timeout interval, it initiates the re-attach process (MLE Child Update Request/Response exchange with its parent).