fix(dotnet): use hasChildrenHint JSON key for browse cross-client parity

Rename the anonymous-object member `hasChildren` → `hasChildrenHint` so the
serialized JSON key matches the Rust and Python CLIs and the library property
HasChildrenHint. Also update the text-output suffix to `hasChildrenHint=` for
consistency.

clients/dotnet/ZB.MOM.WW.MxGateway.Client.Cli/MxGatewayClientCli.cs

@@ -1844,7 +1844,7 @@ public static class MxGatewayClientCli
         string indent = new(' ', level * 2);
         string suffix = hasChildrenHint is null
             ? $"(attrs={galaxyObject.Attributes.Count})"
-            : $"(attrs={galaxyObject.Attributes.Count}, hasChildren={hasChildrenHint.Value})";
+            : $"(attrs={galaxyObject.Attributes.Count}, hasChildrenHint={hasChildrenHint.Value})";
         return $"{indent}{galaxyObject.GobjectId}\t{galaxyObject.TagName}\t{galaxyObject.BrowseName}\t{suffix}";
     }
 
@@ -1853,7 +1853,7 @@ public static class MxGatewayClientCli
         return new
         {
             @object = GalaxyObjectToJsonElement(node.Object),
-            hasChildren = node.HasChildrenHint,
+            hasChildrenHint = node.HasChildrenHint,
             children = node.Children.Select(BrowseTreeNodeToJson).ToArray(),
         };
     }