Summary:
Support launchOptions in bridgeless mode
bypass-github-export-checks

[IOS] [FIXED] - Support launchOptions in bridgeless mode

Pull Request resolved: #43757

Test Plan:
```
useEffect(() => {
    const processInitialURL = async () => {
      const url = await Linking.getInitialURL();
      if (url !== null) {
        console.log(`Initial url is: ${url}`);
      }
    };

    processInitialURL();
  }, []);
```

Reviewed By: javache

Differential Revision: D55790758

Pulled By: cipolleschi

fbshipit-source-id: 0f6aa6bdcebfc5bc42d632bea9193f122c1eb84f

Summary:
Pull Request resolved: #43994

We received [this issue](#43764) from OSS where an app can't connect to Metro on reloads in the following scenario:

* Start the App when metro does not run.
* Observe the error screen
* Start Metro
* Press Reload
* Observe the error message again

While the desired behavior should be to connect to Metro now that this is running.

The root cause of the problem is that the RCTHost is initialized with a value of the `bundleURL` that is `nil`. Upon reload, the RCTHost is **not** recreated: the instance is restarted, but with the previous `bundleURL`, which is still `nil`.

The solution is to initialize the `RCTHost` with a closure that re-evaluate the `bundleURL` whenever it is invoked and to evaluate it only on `start`, to keep the initialization path light.
This way, when the app is started with Metro not running, the `bundleURL` is `nil`. But when it is reloaded with Metro starting, the `bundleURL` is properly initialized.

Note that the changes in this diff are not breaking as I reimplemented (and deprecated) the old initializer so that they should work in the same way.

[iOS][Fixed] - Let RCTHost be initialized with a function to provide the `bundleURL` so that it can connect to metro on Reload when the url changes.

Reviewed By: dmytrorykun

Differential Revision: D55916135

fbshipit-source-id: 6927b2154870245f28f42d26bd0209b28c9518f2