Sort alphabetically without groupings

Can an option be added to sort all imports alphabetically instead of grouping them?

This is the behaviour I get when organising imports in Android Studio.

```
import 'package:alpha/a.dart';
import 'package:beta/b.dart';
import 'package:charlie/c.dart';
import 'package:delta/d.dart';
```

Many thanks
James

Start by locating the import-sorting implementation and the configuration or command entry point where sorting options are defined. Confirm how grouped imports are currently handled, then define completion as an option that produces one alphabetically sorted import list matching the example behavior.

Written by the indexing model from the issue text.