[ECM] Add RequiresPermission annotations

We've recently created a new permission:

    MANAGE_ENHANCED_CONFIRMATION_STATES

The EnhancedConfirmationManager API should be gated by this permission.
So, add the RequiresPermission annotations.

Bug: 320512579
Test: presubmit
Change-Id: Ia04678c8049e46bdd27ae24dd23e7c842e240c63