D8352: Use KIO::PreviewJob::defaultPlugins()

[Elvis Angelaccio]

elvisangelaccio requested changes to this revision.
This revision now requires changes to proceed.

REPOSITORY
  R320 KIO Extras

REVISION DETAIL
  https://phabricator.kde.org/D8352

To: ngraham, #frameworks, broulik, elvisangelaccio, markg