Signing in to hosted nodes works again

Bug Fixes

• Hosted nodes: signing in, including single sign-on from the cloud console, works again on nodes moved to replicated storage. Every sign-in on those nodes failed with "Failed to create session".
• Extensions: installing and updating extensions on those nodes checks the node's own edition and follows the catalog's latest versions again.
• Layouts: a viewer without write access no longer sees an error when the desktop layout repairs a moved item.