message: Validate we never have empty clientId in quorum
  Based on feedback on Teams that we do have cases where clientId ==undefined.
  This should never happen, so adding assert to validate that, and also allow us to react to any bugs if they exist in this space.
diff: @@ -92,6 +92,7 @@ export class QuorumClients extends TypedEventEmitter<IQuorumClientsEvents> imple
  * Adds a new client to the quorum
  */
  public addMember(clientId: string, details: ISequencedClient) {
  + assert(!!clientId, "clientId has to be non-empty string");
  assert(!this.members.has(clientId), 0x1ce /* clientId not found */);
  this.members.set(clientId, details);
  this.emit("addMember", clientId, details);
  @@ -104,6 +105,7 @@ export class QuorumClients extends TypedEventEmitter<IQuorumClientsEvents> imple
  * Removes a client from the quorum
  */
  public removeMember(clientId: string) {
  + assert(!!clientId, "clientId has to be non-empty string");
  assert(this.members.has(clientId), 0x1cf /* clientId not found */);
  this.members.delete(clientId);
  this.emit("removeMember", clientId);
  