Description of problem:
[machines] The VNC console of the VM which is in the remote host is 'Disconnected' or wrongly shown

Packages:
cockpit-machines-269-1.el9.noarch
cockpit-269-1.el9.x86_64
libvirt-8.4.0-1.el9.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Prepare host1 with cockpit env, login cockpit
2. Prepare several vms on host1
3. Add a remote host: host2
4. Switch to 'Virtual Machines' page of the remote host2
5. Create several VMs
6. Switch to the console tab of the VMs which is created in step 5

Actual results:
After step 6, the status of VNC console is 'Disconnected'(there is a "Connect" button, clicking it will not take effect.) or wrongly show the console of the vms on host1

Expected results:
After step 6, the VNC console can be shown correctly