FIX add missing import causing notebook execution failure (#1810)

Co-authored-by: Behnam Ousat <behnamousat@microsoft.com>

Author: behnam-o

doc/code/executor/attack/2_red_teaming_attack.ipynb

@@ -170,6 +170,7 @@
     "    RedTeamingAttack,\n",
     "    RTASystemPromptPaths,\n",
     ")\n",
+    "from pyrit.output import output_attack_async\n",
     "from pyrit.prompt_target import AzureMLChatTarget, OpenAIChatTarget\n",
     "from pyrit.score import SelfAskTrueFalseScorer, TrueFalseQuestion\n",
     "from pyrit.setup import IN_MEMORY, initialize_pyrit_async\n",