False prefer_const_constructors_in_immutables on class that can never be const constructed

[goderbauer]

The following code produces a misleading prefer_const_constructors_in_immutables lint:

@immutable
class Foo {
  Foo(this.list) : assert(list.length > 2); // prefer_const_constructors_in_immutables
  final List<int> list;
}

My understanding from flutter/flutter#102460 (comment) and dart-lang/language#1296 is that this class can never be const-constructed. So, suggesting to give it a const constructor is ... not helpful. :)

Instead, there should actually be the opposite warning: If you do make this constructor const, it should warn that this class can actually never be const constructed and that the const should be removed. I filed #58719 for that.

[srawlins]

Duplicate of #58360