Towards #170067.

Cherry picks #170034, as I think this is causing failures in #170285, which bumps the Dart revision for the initial 3.34 beta release.

As of today, this initial beta cut includes #169273, which was reverted in #170034 because of the failing `test/integration.shard/isolated/dart_data_asset_test.dart` test that is failing in #170285.

FYI @mosuem

As part of steps for creating initial beta release, rolls Dart to `3.9.0-196.1.beta` (dart-lang/sdk@b81ec2c).

Part of #170067.

Using 8ed9edb.

Cherrypick 0cea361 (#170448) to unblock the 3.34 release.

Manual cherrypick because 3.34 is not an active release branch at the moment.

CP of #170490

This PR rolls back auto-migrating iOS apps to UIScene lifecycle. It also updates tests to ensure things work in both a state where UIScene lifecycle is already adopted and when it isn't.

A number of UIScene issues have emerged since landing this in master: #170171

In addition, there's is disagreement over how some of it is implemented.

Impacted Users: All Flutter iOS developers
Impact Description: Some method channels may crash and apps using app lifecycle events may not work properly.
Workaround: Manually removing UIApplicationSceneManifest from Info.plist and potentially also update AppDelegate.swift.
Risk: Low
Test Coverage: Yes
Validation Steps: Run `flutter build ios` and see that `UIApplicationSceneManifest` if not added to Info.plist.

This pull request is created by [automatic cherry pick workflow](https://github.com/flutter/flutter/blob/main/docs/releases/Flutter-Cherrypick-Process.md#automatically-creates-a-cherry-pick-request)
Please fill in the form below, and a flutter domain expert will evaluate this cherry pick request.

### Issue Link:
What is the link to the issue this cherry-pick is addressing?

dart-lang/sdk#60289

### Changelog Description:
Explain this cherry pick in one line that is accessible to most Flutter developers. See [best practices](https://github.com/flutter/flutter/blob/main/docs/releases/Hotfix-Documentation-Best-Practices.md) for examples

Automatically disable `web-experimental-hot-reload` when running flutter using `web-server` device.

### Impact Description:
What is the impact (ex. visual jank on Samsung phones, app crash, cannot ship an iOS app)? Does it impact development (ex. flutter doctor crashes when Android Studio is installed), or the shipping production app (the app crashes on launch)

Without this fix apps launched with`flutter run -d web-server` do not load in the browser. The app is never started.

### Workaround:
Is there a workaround for this issue?

You can work around the issue by passing the same argument that this cherry pick automatically adds: 
`flutter run -d web-server --no-web-experimental-hot-reload`.

### Risk:
What is the risk level of this cherry-pick?

### Test Coverage:
Are you confident that your fix is well-tested by automated tests?

### Validation Steps:
What are the steps to validate that this fix works?

`flutter run -d web-server` and verify that the app can be loaded in a web browser.