[Machines] Can not add disk for transient vm
 
Version-Release number of selected components (if applicable):
cockpit-machines-303-1.el9.noarch
cockpit-305-1.el9.x86_64
libvirt-dbus-1.4.1-5.el9.x86_64
libvirt-client-9.5.0-7.el9_3.x86_64
 
How reproducible:
100%
 
Steps to Reproduce:
1. Prepare a transient vm , e.g. import a cirros and undefine it:

1. virsh undefine cirros

2. Enter the vm details page, click "Add disk", set name and click add

It failed to be added with error:

Disk failed to be added

Requested operation is not valid: transient domains do not have any persistent config 

3. Same error if add disk with "Use existing"
 
Actual results:
See above

 
Expected results:
The disk used to be added successfully

 
Additional info:
Not sure whether this change is intended, please feel free to leave comments if yes.