chore(api): upgrade graphon to v0.3.0 (#35469)

Signed-off-by: -LAN- <laipz8200@outlook.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: WH-2099 <wh2099@pm.me>

api/core/workflow/system_variables.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 from collections import defaultdict
 from collections.abc import Mapping, Sequence
 from enum import StrEnum
-from typing import Any, Protocol, cast
+from typing import Any, Protocol
 from uuid import uuid4
 
 from graphon.enums import BuiltinNodeTypes
@@ -82,13 +82,10 @@ def build_system_variables(values: Mapping[str, Any] | None = None, /, **kwargs:
     normalized = _normalize_system_variable_values(values, **kwargs)
 
     return [
-        cast(
-            Variable,
-            segment_to_variable(
-                segment=build_segment(value),
-                selector=system_variable_selector(key),
-                name=key,
-            ),
+        segment_to_variable(
+            segment=build_segment(value),
+            selector=system_variable_selector(key),
+            name=key,
         )
         for key, value in normalized.items()
     ]
@@ -130,13 +127,10 @@ def build_bootstrap_variables(
 
     for node_id, value in rag_pipeline_variables_map.items():
         variables.append(
-            cast(
-                Variable,
-                segment_to_variable(
-                    segment=build_segment(value),
-                    selector=(RAG_PIPELINE_VARIABLE_NODE_ID, node_id),
-                    name=node_id,
-                ),
+            segment_to_variable(
+                segment=build_segment(value),
+                selector=(RAG_PIPELINE_VARIABLE_NODE_ID, node_id),
+                name=node_id,
             )
         )