Error popup about failure to add files to git can be larger than the screen

It can be triggered by trying to add many files to a project at once using Add existing files.

If Qt Creator failed to add files to git, it shows a large "Failed to add following files to version control (Git") popup and then lists all the files.

If the number of files was large enough, it pushes the top and the bottom side out of screen which prevents the dialog to be read and closed properly.