Fix default Find My Phone ringtone
Previously, if the user hadn't set a ringtone, the code raised an exception (because an empty string isn't an uri). Thus, no sound was played.
This fixes it.
Test Plan: Without having set a ringtone, it works. Otherwise, it works too.
Reviewers: KDE Connect, albertvaka
Reviewed By: KDE Connect, albertvaka
Subscribers: nicolasfella, sredman, KDE Connect
Tags: KDE Connect
Differential Revision: https://phabricator.kde.org/D12070