[ddc] Missing dynamic checks on getter invocations when getter returns dynamic from a type argument

[nshahan]

This code does not throw any errors:

class C {
  List<dynamic> get fn => [
    (int i, {required String s}) {
      return 'hello world';
    },
  ];
}

void main() {
  var c = C();
  c.fn.single();

The compiled code is invoking the closure returned from .single without any checks.