[VCN07.4] Add NOT_VCN_MANAGED for NetworkAgent implementations am: 40bac65ec7 am: 1b910fcec7

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/net/ethernet/+/1563133

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I2ae6137ced9b3dea6e6a9e91c1c00cbdf10aa588
tree: 9bcb4bc6ac74fdf378db79ffa9c8a1eac8ff7b49
  1. service-t/
  2. tests/