Fix policy.path in YAML configs (PR #3145 followup) (#3597)

PR #3145 added YAML support for policy.path but left two bugs:

1. extract_path_fields_from_config only deleted config_data[field] when
   no sibling overrides existed. With siblings, the dict stayed in place
   and draccus crashed decoding it as PreTrainedConfig (no 'type' key).
   Sibling overrides go into _config_yaml_overrides and are applied later
   by from_pretrained(), so the field can always be removed.

2. wrap() updated config_path_cli to the cleaned temp file path but
   never propagated it to the draccus.parse fallback branch. cli_args
   still contained --config_path=<original>, so draccus read the
   original YAML with path: still present.

Tests passed because they (a) called extract_path_fields_from_config
directly and (b) included type: alongside path: in the YAML, sidestepping
both bugs.

Co-authored-by: Steven Palma <imstevenpmwork@ieee.org>

src/lerobot/configs/parser.py

@@ -255,8 +255,7 @@ def extract_path_fields_from_config(config_path: str, path_fields: list[str]) ->
             remaining = config_data[field]
             if remaining:
                 _config_yaml_overrides[field] = _flatten_to_cli_args(remaining)
-            else:
-                del config_data[field]
+            del config_data[field]
             modified = True
 
     if not modified:
@@ -311,7 +310,13 @@ def wrap(config_path: Path | None = None) -> Callable[[F], F]:
                     cli_args = filter_arg("config_path", cli_args)
                     cfg = argtype.from_pretrained(config_path_cli, cli_args=cli_args)
                 else:
-                    cfg = draccus.parse(config_class=argtype, config_path=config_path, args=cli_args)
+                    if config_path_cli:
+                        cli_args = filter_arg("config_path", cli_args)
+                    cfg = draccus.parse(
+                        config_class=argtype,
+                        config_path=config_path_cli or config_path,
+                        args=cli_args,
+                    )
             response = fn(cfg, *args, **kwargs)
             return response