Fix session timeout conversion for Undertow

Closes gh-11283

Author: snicoll

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServerFactory.java

@@ -292,7 +292,7 @@ private DeploymentManager createDeploymentManager(
 		SessionManager sessionManager = manager.getDeployment().getSessionManager();
 		int sessionTimeout = (getSessionTimeout() == null || getSessionTimeout().isZero()
 				|| getSessionTimeout().isNegative() ? -1
-						: (int) getSessionTimeout().toMinutes());
+						: (int) getSessionTimeout().getSeconds());
 		sessionManager.setDefaultSessionTimeout(sessionTimeout);
 		return manager;
 	}