Minimal API validation should support validation attributes on primary constructor parameters

[captainsafia]

The implementation currently doesn't support scenarios like the following:

public class SubType(string? requiredProperty, [StringLength(10)] string? stringWithLength)
{
    [Required]
    public string RequiredProperty { get; } = requiredProperty;

    public string? StringWithLength { get; } = stringWithLength;
}

Where attributes are applied on parameters for a primary constructor for a class. We need to update the constructor discovery logic to be less greedy when discovering primary constructors for non-record types.