Issue #3452009 by John Franklin: Drupal 11 updates

• Style change in OpenIDConnectClientFormBase::exists() to match similar functions (e.g., FilterFormatFormBase::exists() from core)
• Add TypedConfigManagerInterface now required by ConfigFormBase
• Update openid_connect.info.yml
• Closes #3452009

src/Form/OpenIDConnectAccountsForm.php

@@ -106,7 +106,7 @@ class OpenIDConnectAccountsForm extends FormBase {
   /**
    * {@inheritdoc}
    */
-  public function buildForm(array $form, FormStateInterface $form_state, AccountInterface $user = NULL): array {
+  public function buildForm(array $form, FormStateInterface $form_state, ?AccountInterface $user = NULL): array {
     $form_state->set('account', $user);
 
     /** @var \Drupal\openid_connect\OpenIDConnectClientEntityInterface[] $clients */