vm: Don't crash if parent of a host device is missing

Host devices that are referenced by the "parent" attribute of other
host devices are probably always reported by libvirt, but their
retrieval by us might still fail.  Let's not crash in this case.

See https://issues.redhat.com/browse/RHEL-88405

Author: mvollmer

src/components/vm/hostdevs/hostDevAdd.jsx

@@ -70,7 +70,7 @@ function devicesHaveAChild(selectableDevices) {
     });
 
     Object.values(all).forEach(item => {
-        if (item.parent && item.parent !== "computer" && (item.capability.type === "usb_device" || item.capability.type === "pci")) {
+        if (item.parent && all[item.parent] && item.parent !== "computer" && (item.capability.type === "usb_device" || item.capability.type === "pci")) {
             all[item.parent].hasChildren = true;
         }
     });