fix #7108: ui: ipset: do not offer aliases that are already added

When adding an entry to an IPSet, the alias selector lists all aliases,
including those that are already part of the IPSet. Selecting one of
them only results in an "already exists" error from the API.

Pass the current entries of the IPSet to the add window and filter the
matching aliases out of the selector. Aliases are stored in the IPSet
with the same scoped reference the selector uses as value, so an exact
comparison is sufficient.

Signed-off-by: Michal Fox <me@dualfroz.com>
Reviewed-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
Tested-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
Link: https://lore.proxmox.com/20260929142331.2990690-1-me@dualfroz.com

www/manager6/form/IPRefSelector.js

@@ -8,6 +8,9 @@ Ext.define('PVE.form.IPRefSelector', {
 
     ref_type: undefined, // undefined = any [undefined, 'ipset' or 'alias']
 
+    // list of references that should not be offered, e.g. because they are already in use
+    excludeRefs: [],
+
     valueField: 'scopedref',
     displayField: 'ref',
     notFoundIsValid: true,
@@ -54,6 +57,7 @@ Ext.define('PVE.form.IPRefSelector', {
                 property: 'ref',
                 direction: 'ASC',
             },
+            filters: [(rec) => !me.excludeRefs.includes(rec.data.scopedref)],
         });
 
         var columns = [];