BumbleBluetoothTests: Ignore UNAVAILABLE status during factoryReset

During factoryReset a Pandora Server might shutdown itself (Bumble do
this) leading to the stream being closed and the call failing with
an UNAVAILABLE status.
As this is an expected behavior, ignore this error.

Bug: 322509596
Test: atest BumbleBluetoothTests
Flag: Exempt, Test only change
Change-Id: I98f937089413d480519e80b8ad41d7498150437b