Remove update_modem_unlock_retries from MBIM code

Calling the mm_iface_modem_update_unlock_retries function directly from pin_set_enter_ready caused a notification to be send too early with invalid number of attempts to unlock on MBIM modems.
Other modems do not call this function directly but rely on a common call to mm_iface_modem_update_lock_info from send_pin_ready (mm-base-sim.c)

Attaching logs from QMI and MBIM modems to show that OnPropertiesChanged notification from shill is sent in the middle of EnterPin API:

mbim.log

On QMI modems the OnPropertiesChanged is sent at the end (after call to load unlock retries):

qmi.log