remove select from user-grop-relaton model

src/server/models/user-group-relation.js

@@ -85,13 +85,11 @@ class UserGroupRelation {
    * @memberof UserGroupRelation
    */
   static findAllRelationForUserGroup(userGroup) {
-    const User = UserGroupRelation.crowi.model('User');
     debug('findAllRelationForUserGroup is called', userGroup);
     return this
       .find({ relatedGroup: userGroup })
       .populate({
         path: 'relatedUser',
-        select: User.USER_PUBLIC_FIELDS,
       })
       .exec();
   }