framework: $withCount breaks replicate()

• Laravel Version: 5.7.13
• PHP Version: 7.2.9
• Database Driver & Version: mysql / ?

Description:

As in other cases(that have all been fixed I think), a model with a polymorphic relation and a $withCount property fails to replicate()

Steps To Reproduce:

class Board extends Model {
public $withCount = ['profiles'];
public function profiles()
    {
        return $this->morphedByMany(User::class, 'profilable');
    }
}

$b = Board::first();
$b2 = $b->replicate();
$b2->save();

Results in the error: Column not found: 1054 Unknown column 'profiles_count' in 'field list' ...

Expected $b2 to be a new Board instance with same properties as original.