Since Phonon 4.9, this code fails to play a login sound if the sound file is specified as absolute file path (without "file://"). The reason is that QUrl() treats the parameter as Url (not as file path), and this only accidentally worked with earlier Phonon versions but not any more.
This patch uses QUrl::fromUserInput() instead to create a QUrl from the string in the settings file, which fixes the problem.
This is the same change as https://phabricator.kde.org/R289:9db06adc8114163f401417064b07772139bc36bc in knotifications.
A more detailed explanation of the problem can be found in https://bugs.kde.org/show_bug.cgi?id=337276#c12 .
BUG: 392725
FIXED-IN: 5.12.5