"Access Denied" shown when no VDB provider is available
>>> [!note] Migrated issue
<!-- Drupal.org comment -->
<!-- Migrated from issue #3507459. -->
Reported by: [prashant.c](https://www.drupal.org/user/1936756)
Related to !485
>>>
<h3 id="summary-problem-motivation">Problem/Motivation</h3>
<p>When no VDB provider is available, visiting the page /admin/config/ai/vdb_providers shows an "Access Denied" page, even for administrators. This is misleading because the issue is not a permission-related problem but rather the absence of a vector database provider.<br>
<img src="https://www.drupal.org/files/issues/2025-02-18/Screenshot%20from%202025-02-18%2015-24-07.png" alt=""></p>
<h4 id="summary-steps-reproduce">Steps to reproduce</h4>
<p>Visit the page <code>/admin/config/ai/vdb_providers</code>from the admin user without adding or configuring vector database providers.</p>
<h3 id="summary-proposed-resolution">Proposed resolution</h3>
<p>Display informative messages like "No vector database provider available or configured." etc.</p>
<h3 id="summary-remaining-tasks">Remaining tasks</h3>
<h3 id="summary-ui-changes">User interface changes</h3>
<h3 id="summary-api-changes">API changes</h3>
<h3 id="summary-data-model-changes">Data model changes</h3>
issue