In React JS, you can define the assistant persona by passing the `personaOptions` prop to the `AiChat` component.
The `personaOptions` prop is an object with two properties: `assistant` and `user`. The `assistant` property is what you use to
define the assistant persona, as shown in the example below.

```tsx
<AiChat
    adapter={adapter}
    personaOptions={{
        assistant: {
            name: 'HarryBotter',
            avatar: 'https://docs.nlkit.com/nlux/images/personas/harry-botter.png',
            tagline: 'Mischievously Making Magic With Mirthful AI!',
        },
    }}
/>
```

The object passed to the `assistant` property should match the following interface:

```typescript
interface AssistantPersona {
    name: string;
    avatar: string | JSX.Element;
    tagline?: string;
}
```
