New upstream release (2.61.1)

• Stop requiring default provider snaps on image building and first boot if alternative providers are included and available
• Fix auth.json access for login as non-root group ID
• Fix incorrect remodelling conflict when changing track to older snapd version
• Improved check-rerefresh message
• Fix UC16/18 kernel/gadget update failure due volume mismatch with installed disk
• Stop auto-import of assertions during install modes
• Desktop interface exposes GetIdletime
• Polkit interface support for new polkit versions Fix not applying snapd snap changes in tracked channel when remodelling