pass a copy when opening dialog

otherwise, any changes the dialog makes will reflect in the calling
view's object

dashboard/src/components/DomainDialog.vue

@@ -63,7 +63,7 @@ async function onSubmit() {
 
 defineExpose({
   open(d) {
-    d = d || { config: {}, tlsConfig: {}};
+    d = d ? JSON.parse(JSON.stringify(d)) : { config: {}, tlsConfig: {} }; // make a copy
 
     provider.value = d.provider || '';
     dnsConfig.value = d.config;