listen to correct intent extra for defaultSubIdChange

TelephonyRegistry listen for the wrong intent extra PhoneConstants.SLOT
which has been removed recently. Thus when receive default subscription
id changed event, we mistenkenly thought phone ID is invalid,
thus we never update mDefaultPhoneId and mDefaultSubId and fails to
notify listeners on default subscription

Bug: 131915645
Test: Manual
Change-Id: Ibb79e55c0756b30669cbd5c69c181f9f9c4d186b