Currently, the backend responds with a 500 error code when trying to evaluate a report that has no visualization set. Since the backend does not care about the visualization, it should still evaluate the report and send the result to the frontend.

This allows us to fetch data earlier so that we can get rid of a loading delay when the user ultimately selects a visualization. It also allows us to assume that a change in the visualization never needs a re-evaluation of the report, making report updating easier