In Javascript, you can define the bot persona by calling `withPersonaOptions` when creating the `AiChat` component.
The `withPersonaOptions` function takes an object with two properties: `bot` and `user`. The `bot` property is
what you use to define the bot persona, as shown in the example below.

```javascript
const aiChat = createAiChat()
    .withAdapter(adapter)
    .withPersonaOptions({
        bot: {
            name: 'HarryBotter',
            picture: 'https://nlux.ai/images/demos/persona-harry-botter.jpg',
            tagline: 'Mischievously Making Magic With Mirthful AI!'
        }
    });
```

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

```typescript
interface BotPersona {
    name: string;
    picture: string | HTMLElement;
    tagline?: string;
}
```