Remove notification_accepted-related code in StudentTask.
Remove notification_accepted-related code in StudentTask.

rmmaily/expertiza,urmilparikh95/expertiza,KunmiaoYang/expertiza,expertiza/expertiza,kira0992/expertiza,arpitashekhar/expertiza,joshio1/expertiza,urmilparikh95/expertiza,ApertureScienceInnovators/expertiza,rmmaily/expertiza,michaelamoran/expertiza,KunmiaoYang/expertiza,redsock88/expertiza,akshayjain114/expertiza,mhhassan/expertiza,michaelamoran/expertiza,akshayjain114/expertiza,rmmaily/expertiza,ApertureScienceInnovators/expertiza,ApertureScienceInnovators/expertiza,joshio1/expertiza,expertiza/expertiza,redsock88/expertiza,mhhassan/expertiza,kira0992/expertiza,akshayjain114/expertiza,sid5788/expertiza,sid5788/expertiza,urmilparikh95/expertiza,michaelamoran/expertiza,KunmiaoYang/expertiza,mhhassan/expertiza,ApertureScienceInnovators/expertiza,joshio1/expertiza,arpitashekhar/expertiza,urmilparikh95/expertiza,redsock88/expertiza,mhhassan/expertiza,michaelamoran/expertiza,KunmiaoYang/expertiza,sid5788/expertiza,joshio1/expertiza,rmmaily/expertiza,expertiza/expertiza,kira0992/expertiza,expertiza/expertiza,sid5788/expertiza,redsock88/expertiza,arpitashekhar/expertiza,kira0992/expertiza,arpitashekhar/expertiza,akshayjain114/expertiza