Merge "Correct issue with auto disconnect conference where no participants." into sc-dev am: 01fb7193e5 am: 95d24fadd7

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/services/Telephony/+/14905269

Change-Id: I224410a89d51af4258419fe19af7615289d88e7c