All cost details show wrong sum in dashboard

[poacherone]

On the development branch, the column "All cost details" doesn't show the correct total sum, but instead multiplies it (double or tripling the correct sum).

This seems related to #603, but here applies to "All cost details" (and not necessarily to multiple subjects, I've found examples of tripled sums with only one subject) . #576 changes a lot of the code on the sums of the dashboard. Each cost detail has an DISTINCT added before the SUM, and I think the sum of all cost details need a DISTINCT as well to work as intended. A quick local fix seems to have resolved the issue.