refactor: remove unnecessary quotes from ToolPool type hint

- ToolPool is imported at top so quotes not needed in type annotation
- Cleaner type hints following Python typing best practices

🤖 Assisted by Amazon Q Developer

Author: mrlee-amazon

src/strands/experimental/agent_config.py

@@ -18,7 +18,7 @@
 class AgentConfig:
     """Agent configuration with toAgent() method and ToolPool integration."""
 
-    def __init__(self, config_source: str | dict[str, any], tool_pool: "ToolPool | None" = None):
+    def __init__(self, config_source: str | dict[str, any], tool_pool: ToolPool | None = None):
         """Initialize AgentConfig from file path or dictionary.
         
         Args: