Revert "Adds ChooserPinMigration core startable"

Revert submission 22119004-b223249318-chooser-pin-migrate

Reason for revert: <b/275407260>

Reverted changes: /q/submissionid:22119004-b223249318-chooser-pin-migrate

Change-Id: I86e0a0d7d5cfeb729db26f25b0f41ebb18d7bdb5
5 files changed