Fix: Duplicate link search entries for attribute statistic node

Using the output declarations is incorrect because there is a
declaration for each type. Instead loop over the names directly,
since it will make it easier to add an integer mode that only
supports some of the outputs.

source/blender/nodes/geometry/nodes/node_geo_attribute_statistic.cc

@@ -148,8 +148,8 @@ static void node_gather_link_searches(GatherLinkSearchOpParams &params)
     });
   }
   else {
-    for (const SocketDeclarationPtr &socket_decl : declaration.outputs()) {
-      StringRefNull name = socket_decl->name();
+    for (const StringRefNull name :
+         {"Mean", "Median", "Sum", "Min", "Max", "Range", "Standard Deviation", "Variance"}) {
       params.add_item(IFACE_(name.c_str()), [node_type, name, type](LinkSearchOpParams &params) {
         bNode &node = params.add_node(node_type);
         node.custom1 = *type;