Revert^2 "Disable trade-in mode service on phones, TV and auto"

This reverts commit 51f7b73e.

Reason for revert: Regression fixed in ag/30084178
Test: Build, boot cf_x86_64_auto-trunk_staging-userdebug
      Find devicediagnostics.BootCompleteReceiver in logcat
      Make sure no exceptions
Bug: 375454594
Flag: com.android.tradeinmode.flags.enable_trade_in_mode

Change-Id: Ib55794e3e29a69f418b62f41a5c31d6d5c83ce5f