Add unit test init method.

When trying to write some connectionservice unit tests, it became clear
that the mAreAccountsInitialized precondition adds a LOT of overhead
and test scaffolding.  It was easier to just be able to bypass that
in the unit tests.

Test: Added as part of unit test.
Bug: 178649879
Change-Id: Ibed3e69215dad59b252193f701508c18f43b59a2