isColumnVisible(id) {
    let saved = this.storage.getItem(this.getStorageKey()) || {};
    if (saved.columnVisibility && !isNone(saved.columnVisibility[id])) {
      return saved.columnVisibility[id];
    }
    return this.columnSchema.find((x) => x.id === id).visible;
  }
Indicates whether a specific column should be visible
or hidden. The value depends on cached values
and defaults to the original schema.

@method isColumnVisible
@param {String} id
@return {Boolean}