Move DEVICE_ID_DEFAULT from VDM to Context

- DEVICE_ID_DEFAULT refers to the non-virtual default device,
  having this constant in VDM might cause the impression that
  methods that return or make use of this are refering to a
  virtual device when they are not.
- This constant is not extensibly used in VDM, including the method
  isValidVirtualDeviceId for which DEVICE_ID_DEFAULT returns false,
  making it not very clear why this should live in VDM.
- For consistency also move DEVICE_ID_INVALID

Bug: 266178780
Test: just refactor
Change-Id: I31d32cb35c87deb09347fed34a422e457f0f8f3a