BLE: Don't set SC bit in AuthReq for Legacy Device

In android 12, changes from aosp/557339 used to set
secure connection flag to false for legacy ble devices.

Restoring the changes to support legacy devices
as found in Android 12. https://cs.android.com/android/platform/superproject/+/android-12.1.0_r27:system/bt/stack/smp/smp_act.cc;l=180

Bug: 277308810
Tag: #refactor
Test: manual

Change-Id: I43cdca1bb1a2bddf1b343b2c7e94ceb17f4d15da