Enforce setting identity and password for EAP-TTLS/PEAP

EAP-TTLS and EAP-PEAP with phase2 methods that require identity and
password to be set are not checked to make sure these fields are
set and now left empty, to prevent connections that are always
bound to fail.

Bug: 191175291
Test: atest com.android.server.wifi
Test: Settings manual test fails to create such networks without
an identity or password set.

Change-Id: Idf486448f754be1bb76812a79eb98b812664b797
6 files changed