[fix] Membership check of the sender of a certification was buggy

  async isMember(pubkey:string):Promise<boolean> {

    try {

      const idty = await this.iindexDAL.getFromPubkey(pubkey);

      if (idty === null) {

        return false

      if (idty && idty.member) {

	  return true

      }

      return true;

      return false

    } catch (err) {

      return false;

    }