Remove needless loading of highcharts/highstock
Remove needless loading of highcharts/highstock

fix https://github.com/coderdojo-japan/coderdojo.jp/issues/299

yasslab/coderdojo.jp,yasslab/coderdojo.jp,coderdojo-japan/coderdojo.jp,coderdojo-japan/coderdojo.jp,coderdojo-japan/coderdojo.jp,yasslab/coderdojo.jp,coderdojo-japan/coderdojo.jp