[js_interop] No error if a class annotated by `@JSExport()` contains a non-primitive type

[sgrekhov]

There is no expected error below.

import 'dart:js_interop';

@JSExport()
class C {
  final D d;
//      ^
// [analyzer] unspecified
// [web] unspecified
  C(this.d);
}

@JSExport()
class D {
  int bar() => 42;
}

void main() {
  print(C);
}

cc @srujzs

Dart SDK version: 3.10.0-edge.a79b7c6c3594bc30b2bb2160196a8c1b1b3bce00 (main) (Thu Aug 21 23:14:41 2025 -0700) on "linux_x64"

[srujzs]

Not quite non-primitive, but rather a non-JS interop compatible type. For example, JSObject would be allowed but D or Future would not. I also believe this is a duplicate of #56792.