Bugfix/kickoff hangs when llm call fails (#1943)

* Wip to address https://github.com/crewAIInc/crewAI/issues/1934

* implement proper try / except

* clean up PR

* add tests

* Fix tests and code that was broken

* mnore clean up

* Fixing tests

* fix stop type errors]

* more fixes

src/crewai/agent.py

@@ -3,6 +3,7 @@ import shutil
 import subprocess
 from typing import Any, Dict, List, Literal, Optional, Union
 
+from litellm import AuthenticationError as LiteLLMAuthenticationError
 from pydantic import Field, InstanceOf, PrivateAttr, model_validator
 
 from crewai.agents import CacheHandler
@@ -261,6 +262,9 @@ class Agent(BaseAgent):
                 }
             )["output"]
         except Exception as e:
+            if isinstance(e, LiteLLMAuthenticationError):
+                # Do not retry on authentication errors
+                raise e
             self._times_executed += 1
             if self._times_executed > self.max_retry_limit:
                 raise e