DefaultModality(id: String)
DefaultModality is a backwards compatible extension of the attendee id (UUID string) and session token schemas (base 64 string). It appends # to either strings, which indicates the modality of the participant.
For example, attendeeId: "abcdefg" contentAttendeeId: "abcdefg#content" base(contentAttendeeId): "abcdefg" modality(contentAttendeeId): "content" hasModality(contentAttendeeId): true