Use nonebot_plugin_alconna Query to correctly handle the --pingpong
boolean flag. Previously the flag wasn't working because the
parameter wasn't being properly injected.
Changes:
- Import Query from nonebot_plugin_alconna
- Change Option to not have args (just Option('--pingpong'))
- Use Query[bool] type annotation with default Query('pingpong')
- Check pingpong.available to determine if flag was set
