fix: Add _delete_nested_value_custom to recursive function ignore list

The _delete_nested_value_custom function is recursive but has bounded depth
(limited by the number of path segments), preventing infinite recursion.
This is necessary for nested field removal in additional_drop_params.

tests/code_coverage_tests/recursive_detector.py

@@ -35,6 +35,7 @@ IGNORE_FUNCTIONS = [
     "_fix_enum_types",  # max depth set.
     "_collect_argument_paths",  # max depth set.
     "_split_text",  # max depth set.
+    "_delete_nested_value_custom",  # max depth set (bounded by number of path segments).
 ]