services/kservicegroup: include storageId in sorting key
KServiceGroupPrivate::entries uses a QMap for sorting, using the sort key as the key to the map. The sort key is the display name of the application and its generic name (with the order being determined by a parameter). This will fail if two separate apps have the same name and generic name; both evaluate to the same key, so only one is added to the final list and the other just goes away. (This is in particular common for simple apps where the name is itself a generic name, like "Calculator", especially now that apps often don't have a generic name set).
Instead, also add the storageId to the sort key, which should make it unique.
Sometimes it seems to still lead to slightly different keys at least in some locales even if both are the same, but with zh_CN LANGUAGE and Kalk + Gnome Calculator I only get one of them.