[FIX] website: wrong xpath in PageKanban

Since [1], an error was raise because the xpath to add an if attribute
: "//div/t/t[2]/KanbanRecord" wasn't precise anymore and was applied to
the wrong KanbanRecord, removing the correct attribute.

Now a more precise xpath is used.

[1]: https://github.com/odoo/odoo/commit/fa20b8de642fc57e5c6a49ca77c28d4aab150df9

X-original-commit: bc4776d8f532f2c5882bdac1c72ac95c5ade6be9
Part-of: odoo/odoo#112369

addons/website/static/src/components/views/page_kanban.xml

@@ -5,7 +5,7 @@
     <xpath expr="//t[@t-if='groupOrRecord.group']//KanbanRecord" position="attributes">
         <attribute name="t-if">recordFilter(record, props.list.records)</attribute>
     </xpath>
-    <xpath expr="//div/t/t[2]/KanbanRecord" position="attributes">
+    <xpath expr="//div/t/t[@t-else='']/KanbanRecord" position="attributes">
         <attribute name="t-if">recordFilter(groupOrRecord.record, props.list.records)</attribute>
     </xpath>
 </t>