CSD: When testing use random port id

This is necessary since all the patches that were called before CSD is
forced on all devices will be unknown to the sound dose mActiveDevices.
Since we are forcing the CSD on all devices using -1 as the reported
port id.

Test: atest GtsAudioTestCases:SoundDoseTest
Bug: 301527435
Change-Id: I8010d0e2b36700ee7245e60950700f65dcd198cb