Always calculate peer median
Always calculate peer median

Previously, we were only showing the "more assessments needed" message
when there were 0 assessments, but we also need to show it when there are
0 < n < must_be_graded_by assessments for the user, to prevent a blank
area on the grade report. We also supress feedback comments from peers in
this case.

Edraak/edx-ora2,Stanford-Online/edx-ora2,Lektorium-LLC/edx-ora2,EDUlib/edx-ora2,nttks/edx-ora2,EDUlib/edx-ora2,edx/edx-ora2,Edraak/edx-ora2,Stanford-Online/edx-ora2,nttks/edx-ora2,EDUlib/edx-ora2,edx/edx-ora2,miptliot/edx-ora2,miptliot/edx-ora2,Edraak/edx-ora2,edx/edx-ora2,Lektorium-LLC/edx-ora2,miptliot/edx-ora2,nttks/edx-ora2,EDUlib/edx-ora2,Stanford-Online/edx-ora2,Stanford-Online/edx-ora2,Lektorium-LLC/edx-ora2,nttks/edx-ora2,miptliot/edx-ora2,Lektorium-LLC/edx-ora2,Edraak/edx-ora2,edx/edx-ora2