Support creation of self-managed associations in shell

So test VDM use cases may set it when creating a CDM association
via the CDM shell CMD. Otherwise some CDM APIs are impossible to
use because they throw if hte association is not self managed
(e.g. notifyDeviceAppeared)

Fix: 353764525
Flag: EXEMPT unfeasible
Test: n/a
Change-Id: Ifb69caf592d5a93ec01630ba86965058b4982764