[fuzz] implement transmit radio callbacks (#4625)
[fuzz] implement transmit radio callbacks (#4625)

- otPlatRadioTxStarted
- otPlatRadioTxDone

srickardti/openthread,jwhui/openthread,bukepo/openthread,jwhui/openthread,bukepo/openthread,chshu/openthread,chshu/openthread,bukepo/openthread,lanyuwen/openthread,abtink/openthread,bukepo/openthread,jwhui/openthread,librasungirl/openthread,librasungirl/openthread,srickardti/openthread,lanyuwen/openthread,chshu/openthread,abtink/openthread,openthread/openthread,srickardti/openthread,openthread/openthread,chshu/openthread,abtink/openthread,chshu/openthread,chshu/openthread,abtink/openthread,openthread/openthread,lanyuwen/openthread,srickardti/openthread,lanyuwen/openthread,openthread/openthread,librasungirl/openthread,librasungirl/openthread,lanyuwen/openthread,jwhui/openthread,lanyuwen/openthread