framework-wifi: remove duplicate classes

Preconditions & Inet4AddressUtils are statically
linked into both framework-wifi and service-wifi.
This creates duplicate classes, which should be
avoided. Instead, service-wifi should simply refer
to the copy of Preconditions/Inet4AddressUtils in
framework-wifi.

Bug: 153596226
Test: device boots up and connects to wifi
Change-Id: Ie78e5cf0f6ff7bc8a2fa8d7264b742f912601143