Fix test for AdminSessionsManager calling getUser (#22833)

Author: lfolco

app/code/Magento/Security/Test/Unit/Model/AdminSessionsManagerTest.php

@@ -151,7 +151,7 @@ public function testProcessLogin()
             ->method('getSessionId')
             ->willReturn($sessionId);
 
-        $this->authSessionMock->expects($this->once())
+        $this->authSessionMock->expects($this->any())
             ->method('getUser')
             ->willReturn($this->userMock);
         $this->userMock->expects($this->once())