chore: align User.getPassword with the proper interface

Symfony's UserInterface.getPassword is deprecated in favour of the same
method from PasswordAuthenticatedUserInterface.  This fixes deprecation
messages such as this one:  User Deprecated: Since symfony/security-http
5.3: Not implementing the
"Symfony\Component\Security\Core\User\PasswordAuthenticatedUserInterface"
interface in class "UserBase\Client\Model\User" while using
password-based authentication is deprecated.

Author: boite

src/Model/User.php

@@ -4,12 +4,14 @@
 
 use LinkORB\Contracts\UserbaseRole\RoleInterface;
 use RuntimeException;
+use Symfony\Component\Security\Core\User\PasswordAuthenticatedUserInterface;
 use Symfony\Component\Security\Core\User\UserInterface as BaseUserInterface;
 
 final class User implements
     AccountContainerInterface,
     BaseUserInterface,
     LegacyAdvancedUserInterface,
+    PasswordAuthenticatedUserInterface,
     PolicyContainerInterface,
     RoleInterface,
     UserInterface
@@ -32,7 +34,7 @@ final class User implements
     private $accountNonLocked;
 
     private $name;
-    private $password;
+    private $password = '';
     private $roles;
 
     private $createdAt;
@@ -49,7 +51,6 @@ public function __construct(string $name)
         }
 
         $this->name = $name;
-        $this->password = null;
         $this->enabled = true;
         $this->accountNonExpired = true;
         $this->credentialsNonExpired = true;
@@ -109,12 +110,12 @@ public function getRoles()
     /**
      * {@inheritdoc}
      */
-    public function getPassword()
+    public function getPassword(): ?string
     {
         return $this->password;
     }
 
-    public function setPassword($password)
+    public function setPassword(string $password)
     {
         $this->password = $password;
         return $this;