Remove getUsername methods in tests

Author: alamirault

Tests/Authentication/AuthenticationTrustResolverTest.php

@@ -115,10 +115,6 @@ public function setUser($user): void
     {
     }
 
-    public function getUsername(): string
-    {
-    }
-
     public function getUserIdentifier(): string
     {
     }

Tests/Authentication/Token/Fixtures/CustomUser.php

@@ -17,11 +17,6 @@ public function __construct(string $username, array $roles)
         $this->roles = $roles;
     }
 
-    public function getUsername(): string
-    {
-        return $this->username;
-    }
-
     public function getUserIdentifier(): string
     {
         return $this->username;