In commit 9bba65199e,
the QRCodeWidget was put inside a BoxLayout as a workaround to avoid the "copy to clipboard" and
"save as file" functionality grabbing extra whitespace/stretch/padding and putting it into the
exported image.
However, in turn that commit introduced a bug, where making the dialog larger does not make the
QRCodeWidget larger (which worked prior).
This commit tries to fix the regression and also the original bug.
1e97491124