In anticipation of adding Axes to cells, I wanted some test coverage to
be in place before I made the change.
This covers the happy path case as well as focusing on individual
applications. To come are focusing on a measurement and a test for when
the store is unavailable.
Certain aspects of the frontend requires the presence of these three
axes, so part of the contract established is that the backend will
always provide them. Since we centralize creation of
dashboardCellResponses, this is where these axes are added to all cell
responses.
Additionally, because there was previously no coverage over the
dashboard cells endpoints, a test has been added to cover the
DashboardCells method of Service.