Revert "Return the registry in registerNetworkAgent."

This reverts commit 70ede3260cf58b02015a71e60823b004ff4e3d83.

Reason for revert: Likely culprit for b/402365566 - verifying through ABTD before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.

Change-Id: If72cc264c5e505348309c6c11dbbfd11adeaf31b
9 files changed