Fix crash when unpairing a device which supports CSIP

When unpairing a device from settings page, it'll cause
ConcurrentModificationException if the device has CSIP set size > 1.
Iterate the cloned member devices set instead of the original one to
prevent crashing.

Bug: 292190538
Test: unpair a device with 2 members and verify no crash happend
Change-Id: Iaed76612d03a05f31e24ce8ae5b25879d7721e6a