[ECM] Declare MANAGE_ENHANCED_CONFIRMATION_STATES permission (Settings)

Declare the MANAGE_ENHANCED_CONFIRMATION_STATES permission in
packages/apps/Settings/AndroidManifest.xml.

Settings needs this permission to interact with
EnhancedConfirmationManager.

(Note that this is strictly a hint. In practice, Settings uses the
system uid has therefore access to the permission regardless of
whether we declare it here.)

Test: presubmit
Bug: 320512579
Change-Id: Id9eda14b6e3b0d4f0f45b6bb039d9ac84260a740