Avoid busy fetching operations but rely on events websocket

[edlerd]

Done

• remove busy refresh of operations list on instance list
• rely on events websocket for signal to clear cache instead

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 here.
2. Perform the following QA steps:
   • Create a new instance
   • On the instance list: ensure live updates on the creation progress of a new instance still works and the creation line vanishes once the instance is started or created

[webteam-app]

Demo starting at https://lxd-ui-500.demos.haus