dart format produce invalid code

Try formatting:
```dart
int weird(Object o) {
  return switch (o) {
    int i => i, // evil comment
    _ => 42
  };
}
```
produces:
```dart
int weird(Object o) {
  return switch (o) { int i => i, // evil comment _ => 42 };
}
```
which is obviously not valid Dart.

Reproduced with both Dart 3.3.0 and 3.4.0-157.0.dev, and 3.0.0 for that matter.