update viewer after copy/paste

see https://trac.openmicroscopy.org.uk/ome/ticket/7303

To Test:
 * Import  twice the same image
 * Open one image in Full Viewer.
 * Turn off one channel for example. Save. and keep the viewer opened
 * Go to the data manager.
 * Select the image not opened. Right-click and select Rendering Settings >Copy rnd
 * Select in the data manager, the image opened. Right-click and select Rendering Settings >Paste rnd.
 * Thumbnail should be updated, image in the viewer should be updated.
 * Close the viewer. The save dialog should not be displayed.