Improve debug logging for NetworkTimeHelper

Adds dumpsys logging support to NetworkTimeHelper and
implement it for NtpNetworkTimeHelper.

This enables better tracking of whether it currently does what is
expected and help comparison with its proposed replacement.

Bug: 222295093
Test: treehugger / manual build / boot
Change-Id: Idb74ad2842dcc7f521800cdd4f026db1b47dbebc