Fix test mock to use 'context' key instead of 'content' key

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

tests/agent_test.py

@@ -1673,7 +1673,7 @@ def test_agent_uses_task_knowledge():
         try:
             # Configure the mock
             mock_knowledge = MockKnowledge.return_value
-            mock_knowledge.query.return_value = [{"content": content}]
+            mock_knowledge.query.return_value = [{"context": content}]
             
             # Create a real LLM but patch its call method
             agent = Agent(