fix(operations) ensure instance parsing is compatible with future urls

[edlerd]

Done

• ensure operation instance URL parsing is future-proof for https://github.com/lxc/lxd/pull/11795#issuecomment-1580113865

QA

1. Run the LXD-UI:
   • On the demo server via the link posted by @webteam-app below. This is only available for PRs created by collaborators of the repo. Ask @lorumic or @edlerd for access.
   • With a local copy of this branch, run as described in the Readme.
2. Perform the following QA steps:
   • check operation list when snapshotting an instance is linking to the right instance name

[webteam-app]

Demo starting at https://lxd-ui-371.demos.haus

[tomponline]

Thanks!