BREAKING CHANGE: This release has to break some old APIs to stay compatible with React 19.

\#\# `render` is now `async` and should be `await`ed

This is the core change - due to the impementation of sibling prerendering on the React side, rendering has become more `async` and tests that interacted with `render` in a synchronous fashion would end up with not-resolving suspense boundaries.

Please adjust your tests accordingly:

```diff
  const {takeRender, render} = createRenderStream({ /* ... */ })
-  const utils = render(<Counter />)
+  const utils = await render(<Counter />)
```

\#\# enforcing of `IS_REACT_ACT_ENVIRONMENT == false`

In combination with [issues we have have seen in the past](facebook/react#29855), we have deduced that the testing approach of this library only really works in a "real-world" scenario, not in an `act` environment.

As a result, we will now throw an error if you try to use it in an environment where `IS_REACT_ACT_ENVIRONMENT` is truthy.

We are shipping a new tool, `disableActEnvironment` to prepare your environment for the duration of a test in a safe manner.

This helper can either be used with explicit resource management using the `using` keyword:

```ts
test('my test', () => {
  using _disabledAct = disableActEnvironment()

  // your test code here

  // as soon as this scope is left, the environment will be cleaned up
})
```

of by manually calling `cleanup`:

```ts
test('my test', () => {
  const {cleanup} = disableActEnvironment()

  try {
    // your test code here
  } finally {
    cleanup()
  }
})
```

This function does not only adjust your `IS_REACT_ACT_ENVIRONMENT` value, but it will also temporarily adjust the `@testing-library/dom` configuration in a way so that e.g. calls to `userEvent` will not automatically be wrapped in `act`.

Of course you can also use this tool on a per-file basis instead of a per-test basis, but keep in mind that doing so will break any React Testing Library tests that might be in the same file.

\#\# `render` is now it's own implementation

Previously, we used the `render` function of React Testing Library, but with the new restrictions this is no longer possible and we are shipping our own implementation.

As a result, some less-common options are not supported in the new implementation.
If you have a need for these, please let us know!

* `hydrate` was removed
* `legacyRoot` was removed. If you are using React 17, it will automatically switch to `ReactDOM.render`, otherwise we will use `createRoot`

> [!CAUTION]
> React 17 does not look for `IS_REACT_ACT_ENVIRONMENT` to determine if it is running in an `act`-environment, but rather `typeof jest !== "undefined"`.
> If you have to test React 17, we recommend to patch it with a [`patch-package` patch](https://github.com/apollographql/apollo-client/blob/8a4738a8ad7284d247513671628a4ac5917e104c/patches/react-dom-17+17.0.2.patch)

\#\#  `renderToRenderStream` was removed

As you now have to `await` the `render` call, `renderToRenderStream` had no real value anymore.

Where previously, the second line of
```js
const renderStream = renderToRenderStream(<Component />, combinedOptions)
// this was optional in the past
const utils = await renderStream.renderResultPromise
```
could be omitted and could save you some code, now that second line would become required.

This now was not any shorter than calling `createRenderStream` and `renderStream.render` instead, and as both of these APIs now did the same thing in a different fashion, this would lead to confusion to no more benefit, so the API was removed.