Clean up unneeded code for namespace-less loading of applets
In https://phabricator.kde.org/D1851 it was added back, but on the same day in plasma-workspace commit 42b64e1bd2c64a43f47a1f9d0b8895e3f3fcea9d landed, which made the change obsolete.
Having this logic around slows down filling the startup cache.