fix crash when not using query

[lfuelling]

This PR fixes the Something went wrong fetching AI response. error before any request happens.

This appears for example with the example code in the readme.

[niels-bosman]

@lfuelling We use body in this way and we are not getting any errors, can you check if this is still happening?

const chat = useChatStream({
    options: {
      url: 'URL',
      method: 'POST',
      body: {
        email: email,
      },
    },
    method: { type: 'body', key: 'query' },
  });