fix: Resolve lint and type-checking issues in A2A integration

- Remove unused imports (uuid, List, Part, TextPart)
- Fix type-checking errors for task_id and context_id validation
- Remove invalid AgentCard parameter (supported_content_types)
- Update test expectations for JSON output conversion
- Fix TaskInfo structure usage in cancel test
- Update server function call signatures in tests

All A2A tests now pass (34 passed, 2 skipped)

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

tests/a2a/test_task_info.py

@@ -0,0 +1,51 @@
+"""Tests for TaskInfo dataclass."""
+
+import pytest
+from datetime import datetime
+from unittest.mock import Mock
+
+try:
+    from crewai.a2a.crew_agent_executor import TaskInfo
+    A2A_AVAILABLE = True
+except ImportError:
+    A2A_AVAILABLE = False
+
+
+@pytest.mark.skipif(not A2A_AVAILABLE, reason="A2A integration not available")
+class TestTaskInfo:
+    """Test TaskInfo dataclass functionality."""
+    
+    def test_task_info_creation(self):
+        """Test TaskInfo creation with required fields."""
+        mock_task = Mock()
+        started_at = datetime.now()
+        
+        task_info = TaskInfo(task=mock_task, started_at=started_at)
+        
+        assert task_info.task == mock_task
+        assert task_info.started_at == started_at
+        assert task_info.status == "running"
+    
+    def test_task_info_with_custom_status(self):
+        """Test TaskInfo creation with custom status."""
+        mock_task = Mock()
+        started_at = datetime.now()
+        
+        task_info = TaskInfo(
+            task=mock_task,
+            started_at=started_at,
+            status="completed"
+        )
+        
+        assert task_info.status == "completed"
+    
+    def test_task_info_status_update(self):
+        """Test TaskInfo status can be updated."""
+        mock_task = Mock()
+        started_at = datetime.now()
+        
+        task_info = TaskInfo(task=mock_task, started_at=started_at)
+        assert task_info.status == "running"
+        
+        task_info.status = "cancelled"
+        assert task_info.status == "cancelled"