Images removed from 'orphaned' into new Dataset. See #11493

See https://trac.openmicroscopy.org.uk/ome/ticket/11493

To test:
 - Select orphaned images in webclient, create Dataset (either via right-click menu or toolbar button). The selected images should be removed from under 'orphaned' (and appear under the new Dataset).
 - Also check that other P/D creation is still working as normal (regression test).