chore(footer): replace Twitter with X logo (#10438)

Signed-off-by: TATHAGATA ROY <[email protected]>
Co-authored-by: Claas Augner <[email protected]>

Author: roy9495

Diff for: client/src/assets/icons/twitter-x.svg

@@ -10,7 +10,7 @@ $icons: "add-filled", "add", "altname", "bell", "bell-filled", "bell-ring",
   "previous", "queue", "queued", "quote", "return", "safari", "samsunginternet",
   "search", "send", "server", "sidebar", "simple-firefox", "small-arrow",
   "theme-light", "star-filled", "star", "theme-os-default", "thumbs-down",
-  "thumbs-up", "trash", "trash-filled", "twitter", "unknown", "warning",
+  "thumbs-up", "trash", "trash-filled", "twitter-x", "unknown", "warning",
   "webview", "yes", "yes-circle";
 
 .icon {

Diff for: client/src/assets/icons/twitter.svg

@@ -34,12 +34,14 @@ export function Footer() {
             </li>
             <li>
               <a
-                className="icon icon-twitter"
+                className="icon icon-twitter-x"
                 href="https://twitter.com/mozdevnet"
                 target="_blank"
                 rel="noopener noreferrer"
               >
-                <span className="visually-hidden">MDN on Twitter</span>
+                <span className="visually-hidden">
+                  MDN on X (formerly Twitter)
+                </span>
               </a>
             </li>
             <li>