Revert "Create a system API to allow preinstalled assistants to receive training data events."

This reverts commit d4051e73715dc3fced6d722dc62840172467b132.

Revert Reason: Deprecate trusted fed-hot.
Test: atest -c CtsVoiceInteractionTestCases:HotwordDetectionServiceBasicTest
Bug:322391277


Change-Id: I9a73cc03c19eaca489dd7ad3d665b752191c289e
5 files changed