refactor: simplify variable pool key structure and improve type safety (#23732)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/core/workflow/utils/variable_utils.py

@@ -1,29 +0,0 @@
-from core.variables.segments import ObjectSegment, Segment
-from core.workflow.entities.variable_pool import VariablePool, VariableValue
-
-
-def append_variables_recursively(
-    pool: VariablePool, node_id: str, variable_key_list: list[str], variable_value: VariableValue | Segment
-):
-    """
-    Append variables recursively
-    :param pool: variable pool to append variables to
-    :param node_id: node id
-    :param variable_key_list: variable key list
-    :param variable_value: variable value
-    :return:
-    """
-    pool.add([node_id] + variable_key_list, variable_value)
-
-    # if variable_value is a dict, then recursively append variables
-    if isinstance(variable_value, ObjectSegment):
-        variable_dict = variable_value.value
-    elif isinstance(variable_value, dict):
-        variable_dict = variable_value
-    else:
-        return
-
-    for key, value in variable_dict.items():
-        # construct new key list
-        new_key_list = variable_key_list + [key]
-        append_variables_recursively(pool, node_id=node_id, variable_key_list=new_key_list, variable_value=value)