fix: table name (#1879)

## Description
Change table name of simple agent

## Type of change

Please check the options that are relevant:

- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Model update
- [ ] Infrastructure change

## Checklist

- [x] My code follows Phidata's style guidelines and best practices
- [x] I have performed a self-review of my code
- [ ] I have added docstrings and comments for complex logic
- [ ] My changes generate no new warnings or errors
- [ ] I have added cookbook examples for my new addition (if needed)
- [ ] I have updated requirements.txt/pyproject.toml (if needed)
- [ ] I have verified my changes in a clean environment

## Additional Notes

Include any deployment notes, performance implications, or other
relevant information:

cookbook/playground/demo.py

@@ -22,7 +22,7 @@
     role="Answer basic questions",
     agent_id="simple-agent",
     model=OpenAIChat(id="gpt-4o-mini"),
-    storage=SqliteAgentStorage(table_name="web_agent", db_file=agent_storage_file),
+    storage=SqliteAgentStorage(table_name="simple_agent", db_file=agent_storage_file),
     add_history_to_messages=True,
     num_history_responses=3,
     add_datetime_to_instructions=True,