Fix: Error message when logging in is shown properly

[JacoKoster]

Instead of showing a stringified version of the json response, we show the message instead.

[JacoKoster]

Probably a silly request, but it shows in this PR. The prettier standard of 80 columns feels a bit too short, what do we think of changing this to 100?

[tkurki]

I'm in the "go with the least prettier config" camp, but am pretty ambivalent about line length. Since I recently learned about https://www.stefanjudis.com/today-i-learned/how-to-exclude-commits-from-git-blame/ my earlier objection about noise in diffs is less revelant, if not quite nonexistent.

[JacoKoster]

As i am usually working on a wide screen, i pretty much always find that the 80 columns works counter intuitively of the goal of making the lines more readable. For now i'll stick with the default :)