Fix issue in call forwarding erase response handling

Hi, Issue observed in call forwarding feature information list parsing. Due to this, isimodem reports Erase failure to the core even when the Erase request is successfully handled by the network. Considering the current logic, this is the fix that can be provided without changes to other parts of the code. One of the other option is to initialize the status in the calling function and check its validity before the usage. Regards, Jeevaka