fix: remove @DataClass from SplitPayloadAttackResult for pydantic compat

AttackResult is now a pydantic BaseModel on main. The @DataClass
decorator was preventing pydantic field inheritance (specifically
atomic_attack_identifier). Also fix Optional[] -> X | None per ruff.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Eve Kazarian

pyrit/executor/attack/multi_turn/split_payload.py

@@ -8,7 +8,7 @@
 import logging
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Optional, cast
+from typing import TYPE_CHECKING, Any, cast
 
 from pyrit.common.apply_defaults import REQUIRED_VALUE, apply_defaults
 from pyrit.common.path import EXECUTOR_SEED_PROMPT_PATH
@@ -80,7 +80,6 @@ class SplitPayloadAttackContext(MultiTurnAttackContext[Any]):
     design_pattern: str = "component_assembly"
 
 
-@dataclass
 class SplitPayloadAttackResult(AttackResult):
     """Result of the split-payload attack strategy execution."""
 
@@ -161,9 +160,9 @@ def __init__(
         *,
         objective_target: PromptTarget = REQUIRED_VALUE,  # type: ignore[ty:invalid-parameter-default]
         attack_adversarial_config: AttackAdversarialConfig,
-        attack_converter_config: Optional[AttackConverterConfig] = None,
-        attack_scoring_config: Optional[AttackScoringConfig] = None,
-        prompt_normalizer: Optional[PromptNormalizer] = None,
+        attack_converter_config: AttackConverterConfig | None = None,
+        attack_scoring_config: AttackScoringConfig | None = None,
+        prompt_normalizer: PromptNormalizer | None = None,
         design_pattern: str = "component_assembly",
         max_turns: int = 5,
         max_regenerations: int = 3,
@@ -270,7 +269,7 @@ def __init__(
         self._max_turns = max_turns
         self._max_regenerations = max_regenerations
 
-    def get_attack_scoring_config(self) -> Optional[AttackScoringConfig]:
+    def get_attack_scoring_config(self) -> AttackScoringConfig | None:
         """
         Get the attack scoring configuration.