fixes #7360 / BZ 1120595 - UI: Product: fix Sync Now behavior

This commit addresses 2 small issues related to the 'Sync Now' button
on a the Product -> Details pane.  After the user clicks the button
and a response is received from the server:
1. switch the button back from 'Syncing...' to 'Sync Now'
2. display a notification to the user to indicate that the sync has
   been scheduled