chore(datepicker): fix customClass demo
chore(datepicker): fix customClass demo

Closes #4877

looker/bootstrap,infowrap/bootstrap,RobJacobs/bootstrap,icfantv/bootstrap,fpipita/bootstrap,RobJacobs/bootstrap,connyay/bootstrap,deeg/bootstrap,BookingBug/bootstrap,shootermv/bootstrap,vfiles/bootstrap,Foxandxss/bootstrap,benhalverson/bootstrap,benhalverson/bootstrap,byronigoe/bootstrap,292388900/bootstrap,caoruiy/bootstrap,justin-john/bootstrap-1,mabi/bootstrap,Lincoln-xzc/angular-ui-bootstrap,byronigoe/bootstrap,matteopic/bootstrap,292388900/bootstrap,christor/bootstrap,benhalverson/bootstrap,fpipita/bootstrap,angular-ui/bootstrap,Kpler/bootstrap,caoruiy/bootstrap,shootermv/bootstrap,burlhock/bootstrap,wesleycho/bootstrap,deeg/bootstrap,looker/bootstrap,Foxandxss/bootstrap,matteopic/bootstrap,Kpler/bootstrap,shiftagent/ui-bootstrap,connyay/bootstrap,burlhock/bootstrap,vfiles/bootstrap,infowrap/bootstrap,Lincoln-xzc/angular-ui-bootstrap,Servoy/bootstrap,icfantv/bootstrap,wesleycho/bootstrap,mabi/bootstrap,shiftagent/ui-bootstrap,BookingBug/bootstrap,benhalverson/bootstrap,justin-john/bootstrap-1,Servoy/bootstrap,angular-ui/bootstrap,christor/bootstrap