Update GATT disconnect reason in case of bond loss

Native stack disconnects the ACL connection when the remote bond loss is detected. The resulting GATT disconnect callback from native contains HCI_ERR_CONN_CAUSE_LOCAL_HOST as the disconnection reason. Sending HCI_ERR_AUTH_FAILURE instead as the GATT disconnection reason code is more meaningful for the applications.

Change-Id: Iec797412221d34fd07524040ac27c5fd1897e2b0
Test: mmm packages/modules/Bluetooth
Flag: EXEMPT trivial bugfix
Bug: 399219246