Remove Deprecated-At-Birth APIs from PDCS

Two APIs were added as @SystemApi and then @Deprecated within
the same API level (RVC). These methods were never exposed
publicly, and instead were replaced with more-appropriate
named methods that were added to the public API. As such they
were not fully deleted in RVC but were never exposed and expected
to be deleted following SDK finalization. This CL does precisely
that - removes all traces of these methods, as per the will of
the API Council.

-Remove #getDataConnectionLinkProperties()
-Remove #getDataConnectionNetworkType()

Bug: 152787887
Test: make update-api && make
Change-Id: I89463b0bd641e9316f90fe4f535d326f6e74a061