Remove Parcelable interface from DefaultNetworkEvent

This patch takes advantage of the direct DefaultNetworkMetrics interface
between ConnectivityService and IpConnectivityMetrics and removes the
Parcelable interface from DefaultNetworkEvent.

IpConnectivityMetrics, IpConnectivityEventBuilder and associated tests
are updated as necessary.

Bug: 34901696
Test: runtest frameworks-net
Change-Id: I59b6e04fc126051320d08a422cfbd4d27042123e
6 files changed