Update the known CDM associations when creating a VD

In case the association was just created, VDM may have not
been notified about it yet, so calls to getAllPersistentDeviceIds
would return a wrong value.

This race also causes a tiny flakiness in some tests.

Solving by simply adding the relevant association to the known
ones when creating a VD (after verifying the association)

Fix: 436890446
Test: presubmit
Flag: EXEMPT bugfix
Change-Id: I94320f379cc9d2d8380564ac63cb3e06d9276a74