Fix TraceBatchManager authentication handling for issue #3559

- Move get_auth_token() call inside try-catch block in TraceBatchManager.__init__
- This allows graceful handling of AuthError when no authentication token is present
- Crews can now work without authentication by using ephemeral batches
- Add test to verify TraceBatchManager handles missing auth gracefully
- Add standalone test script that confirms the fix works correctly

Fixes issue where recent changes broke previously running crews due to
mandatory authentication in the tracing system.

Co-Authored-By: João <joao@crewai.com>

test_tracing_auth.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""
+Test script for issue #3559 - TraceBatchManager authentication handling
+"""
+
+import sys
+sys.path.insert(0, '/home/ubuntu/repos/crewAI/src')
+
+def test_tracing_auth_issue():
+    """Test that tracing authentication issue is fixed"""
+    
+    try:
+        from crewai.events.listeners.tracing.trace_batch_manager import TraceBatchManager
+        from crewai.cli.authentication.token import AuthError
+        from unittest.mock import patch
+        
+        print("Test 1: TraceBatchManager creation without authentication")
+        
+        with patch(
+            "crewai.events.listeners.tracing.trace_batch_manager.get_auth_token",
+            side_effect=AuthError("No token found, make sure you are logged in")
+        ):
+            batch_manager = TraceBatchManager()
+            print(f"✓ TraceBatchManager created successfully with empty API key: '{batch_manager.plus_api.api_key}'")
+            
+            batch = batch_manager.initialize_batch({"user_id": "test"}, {"crew_name": "test"})
+            if batch is not None:
+                print(f"✓ Batch initialized successfully: {batch.batch_id}")
+            else:
+                print("✗ Batch initialization returned None")
+                return False
+                
+    except Exception as e:
+        print(f"✗ TraceBatchManager test failed: {e}")
+        import traceback
+        traceback.print_exc()
+        return False
+    
+    try:
+        from crewai import Agent, Crew, Task, LLM
+        
+        print("\nTest 2: Crew creation without authentication")
+        
+        with patch(
+            "crewai.events.listeners.tracing.trace_batch_manager.get_auth_token",
+            side_effect=AuthError("No token found, make sure you are logged in")
+        ):
+            agent = Agent(
+                role="Test Agent",
+                goal="Complete a simple task",
+                backstory="A test agent for reproducing the bug",
+                llm=LLM(model="gpt-4o-mini", api_key="fake-key")
+            )
+            
+            task = Task(
+                description="Say hello world",
+                expected_output="A greeting message",
+                agent=agent
+            )
+            
+            crew = Crew(
+                agents=[agent],
+                tasks=[task],
+                verbose=False
+            )
+            
+            print("✓ Crew created successfully without authentication errors")
+            
+    except Exception as e:
+        print(f"✗ Crew creation test failed: {e}")
+        import traceback
+        traceback.print_exc()
+        return False
+    
+    return True
+
+if __name__ == "__main__":
+    print("Testing TraceBatchManager authentication handling...")
+    success = test_tracing_auth_issue()
+    if not success:
+        print("\nFAILED: Issue #3559 still exists")
+        exit(1)
+    else:
+        print("\nPASSED: Issue #3559 appears to be fixed")