fix: remove unused prop 'message' from Child component

[naokihaba]

📚 Description

Remove unused message prop that was causing console warning.

The content is passed via instead of props, so the message prop definition was unnecessary.

Console warning before fix

  [3:17:19]  WARN  [Vue warn]: Missing required prop: "message"
    at <Child name="John Doe" onUpdate:name=fn<updateName> >
    at <App>
    at <NuxtRoot>

Before	After

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