Initialize 3gpp interface to read IMEI in FAILED state
It was not possible to read IMEI of modem when SIM was not inserted or initialization failed due to modem facility locks.
This change allows to run one more step of broadband modem initialization (INITIALIZE_STEP_IFACE_3GPP) before going to step FALLBACK_LIMITED when sim is missing. Only basic initialization of 3gpp is performed (like when sim is locked) to read imei and state of facility locks.