chore: revert twitter logo change (#6096)

Author: Joan Fontanals

docs/_templates/page.html

@@ -192,7 +192,7 @@
                             <a class='social-btn' href="https://youtube.com/c/jina-ai" aria-label="YouTube"
                                target="_blank" rel="noreferrer"> <i class="fab fa-youtube"></i></a>
                             <a class='social-btn' href="https://twitter.com/JinaAI_" aria-label="Twitter"
-                               target="_blank" rel="noreferrer"> <i class="fa-brands fa-x-twitter"></i></a>
+                               target="_blank" rel="noreferrer"> <i class="fab fa-twitter"></i></a>
                             <a class='social-btn' href="https://www.linkedin.com/company/jinaai/" aria-label="LinkedIn"
                                target="_blank" rel="noreferrer"> <i class="fab fa-linkedin"></i></a>
                         </div>