[Gradebook] Remove "Student Names" and "Assignment Names" drop down filters / Re-provide "Sections" without hoops

[jwagoner]

Problem statement:

Wasted screen space on Gradebook view Inefficient / excessive steps to select Section in Gradebook view

Proposed solution:

Allow option to deselect current permanent view of "Student Names" and "Assignment Names" so that I can more easily view students within the Gradebook view (not a fan of typing and mousing if I can avoid it). Allow option to select "Sections" as a permanent view, as it was allowed recently before update, to more easily navigate between sections instead of selecting, clicking and scrolling multiple times within a mixed menu to change.

User role(s):

instructor