Create voice-activation permission

 This permission will be a signature|privileged|appop type. The
 permission status will be pre-grant to privileged assistant apps via allowlist.
 The appop protection flag allows user controls on the access status via flipping the op mode via UI toggle.

 The default op mode value = MODE_DEFAULT. The permission status is
 granted if the app is allowlisted by the OEM. The inital access is
 decided by the permission status.

 When user deny the access, op mode = MODE_IGNORED, access denied.
 When user allow the access, op mode = MODE_ALLOWED, access allowed,
 regardless of permission status.

 Detailed design option seen in https://docs.google.com/document/d/15Rn363JZfe9NCexOWnPYzSkaAo4XqP4JBqCQuj9UyoY/edit?resourcekey=0-EM3T-DFn2ymF7C-1_p-3Ow#bookmark=id.5jfcta6t9r7k

Bug: 289087269
Bug: 287084170
Test: presubmit
Change-Id: Ib30ef2d8813ac5eb74457c6b8f173bffafea52ce