Fix setPairingConfirmation permissions issue (2/2)

setPairingConfirmation was set to only require BLUETOOTH_ADMIN
permission which shouldn't be able to set the confirmation itself.

This is restricted to BLUETOOTH_PRIVILEGED permission.

RM-290

Bug: 29043989
Change-Id: I887de32d156e672ec44aa0b286cd7ea7f9f8ad55
(cherry picked from commit 93326cfd)