[kio] Fix file browsing with non-KIO file managers

For starting file browsing via Plasmoid or Indicator we call KRun on the kdeconnect:// URL. KRun does some magic to translate the KIO url to a local URL for non-KIO file managers (i.e. most file managers except dolphin). This works by copying the directory to a cache location. This 1) fails with "A folder foo already exists" and 2) is inefficient as our FS is locally mounted anyway and the KioSlave is just a shim. For cases like this KIO has the UDS_LOCAL_PATH property. We need to set this while stat'ing (and not listing) because this is when KRun checks for it.