Description of problem:
Prepare a VM without checking "Immediately start VM". Click "Install". Then delete the VM, the VM will still exist

Version-Release number of selected components (if applicable):
cockpit-machines-238.2-1.el8.noarch
cockpit-238.2-1.el8.x86_64
libvirt-dbus-1.3.0-2.module+el8.3.0+6423+e4cb6418.x86_64

How reproducible:
100%

Steps to Reproduce:
1 Prepare a VM without checking "Immediately start VM"
2 Click "Install"
3 Delete the VM

Actual results:
1 The VM is still exist after deletion

Expected results:
1 The VM can be deleted correctly

Additional info: