Reduce log spam in DcTracker and DataEnabledSettings

For a device in a normal state (connected), just opening Settings >
Network & internet triggers this log, which can flush useful info out of
the local log buffer. We can keep the CONNECTING and DISCONNECTING logs
because those are less common but we should remove the log for
CONNECTED.

In DataEnabledSettings we also only local log when the setting actually
changes.

Bug: 133852635
Test: manual
Merged-In: I3a231db8428c26263f892aa5ea0ebe89222cdd61
Change-Id: I3a231db8428c26263f892aa5ea0ebe89222cdd61
(cherry picked from commit 23361e6e)