[fix] retrievePeripheralWithUUIDString 增加一个对生成uuid空值的判断，否则传入空的uuidstring会导致app crash
[fix] retrievePeripheralWithUUIDString 增加一个对生成uuid空值的判断，否则传入空的uuidstring会导致app crash

coolnameismy/BabyBluetooth,coolnameismy/BabyBluetooth