Reverts flutter/flutter#137945
Initiated by: HansMuller
This change reverts the following previous change:
Original Description:
This PR introduces `AnimationStyle`, it is used to override default animation curves and durations in several widgets.

fixes  [Add the ability to customize MaterialApp theme animation duration](https://github.com/flutter/flutter/issues/78372)
fixes [Allow customization of showMenu transition animation curves and duration](https://github.com/flutter/flutter/issues/135638)

Here is an example where popup menu curve and transition duration is overriden:

```dart
          popUpAnimationStyle: AnimationStyle(
            curve: Easing.emphasizedAccelerate,
            duration: Durations.medium4,
          ),
```

Set `AnimationStyle.noAnimation` to disable animation.
```dart
    return MaterialApp(
      themeAnimationStyle: AnimationStyle.noAnimation,
```