Refactor auto login to avoid setState in useEffect

The previous implementation triggered handleLogin inside a useEffect on
mount, which caused a synchronous setState call and an additional render
cycle.
This approach is not recommended by React and is flagged by eslint as it
can cause unnecessary rerenders.

Auto login is now handled during render using a guarded condition to
ensure it runs only once.

Signed-off-by: Jasmina <jasmina.piric@secomind.com>

Author: JasminaPiric

frontend/src/pages/Login.tsx

@@ -18,7 +18,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useState } from "react";
 import { FormattedMessage, useIntl } from "react-intl";
 import { useLocation, useNavigate } from "react-router-dom";
 import Alert from "react-bootstrap/Alert";
@@ -52,6 +52,7 @@ const LoginPage = () => {
   const [validated, setValidated] = useState(false);
   const [errorFeedback, setErrorFeedback] = useState<React.ReactNode>(null);
   const [isLoggingIn, setIsLoggingIn] = useState(false);
+  const [autoLoginTriggered, setAutoLoginTriggered] = useState(false);
   const auth = useAuth();
   const intl = useIntl();
   const navigate = useNavigate();
@@ -99,13 +100,14 @@ const LoginPage = () => {
       setFormData((data) => ({ ...data, [field]: value }));
     }, []);
 
-  useEffect(() => {
-    if (initialFormData.tenantSlug && initialFormData.authToken) {
-      handleLogin(initialFormData);
-    }
-    // Run once on mount
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, []);
+  if (
+    !autoLoginTriggered &&
+    initialFormData.tenantSlug &&
+    initialFormData.authToken
+  ) {
+    setAutoLoginTriggered(true);
+    handleLogin(initialFormData);
+  }
 
   return (
     <AuthPage>