redirectUri must be not null or using an optional string

[kschroeer]

I used the script at /data/oauth2.sql to create the database model. Here I find the following table definition:

CREATE TABLE `oauth_clients` (
  ...
  `redirect` varchar(255) DEFAULT NULL,
  ...
);

But the constructor in Mezzio\Authentication\OAuth2\Entity\ClientEntity looks like this:

public function __construct(string $identifier, string $name, string $redirectUri, bool $isConfidential = false)

Either the column in the database must not allow NULL values or the parameter $ redirectUri must be an optional. But that's not how it works.