fix(loginV2): hide sign-in-with-idp if none are configured (#10402)

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# Which Problems Are Solved

Don't show the external IdP section, if none are configured.

# How the Problems Are Solved

- Checks if the length of `identityProviders` is non-empty.

# Additional Changes

- Added 2 additional null-checks for `identityProviders`

# Additional Context

- Closes #10401

Co-authored-by: Max Peintner <max@caos.ch>
Co-authored-by: Livio Spring <livio.a@gmail.com>
(cherry picked from commit a718267191)

apps/login/src/app/(login)/idp/page.tsx

@@ -38,7 +38,7 @@ export default async function Page(props: {
           <Translated i18nKey="description" namespace="idp" />
         </p>
 
-        {identityProviders && (
+        {!!identityProviders?.length && (
           <SignInWithIdp
             identityProviders={identityProviders}
             requestId={requestId}

apps/login/src/app/(login)/loginname/page.tsx

@@ -78,7 +78,7 @@ export default async function Page(props: {
           allowRegister={!!loginSettings?.allowRegister}
         ></UsernameForm>
 
-        {identityProviders && loginSettings?.allowExternalIdp && (
+        {loginSettings?.allowExternalIdp && !!identityProviders?.length && (
           <div className="w-full pb-4 pt-6">
             <SignInWithIdp
               identityProviders={identityProviders}

apps/login/src/components/sign-in-with-idp.tsx

@@ -80,7 +80,7 @@ export function SignInWithIdp({
       <p className="ztdl-p text-center">
         <Translated i18nKey="orSignInWith" namespace="idp" />
       </p>
-      {!!identityProviders.length && identityProviders?.map(renderIDPButton)}
+      {!!identityProviders?.length && identityProviders?.map(renderIDPButton)}
       {state?.error && (
         <div className="py-4">
           <Alert>{state?.error}</Alert>