SystemUI: Fix 5G icon not restore after phone is killed

SystemUI doesn’t receive onBindingDied when phone process is killed.
It leads to SystemUI still references the proxy for IExtTelephony
instance which is already died.

In this case, re-binder IExtTelephony service when DeadObjectException
is caught.

Change-Id: I36f2be9fee1ed57fa7783186048481e9e4042bf2
CRs-Fixed: 2407542