Fix unfollow button being out of frame on small screens on old browsers (#29923)

app/javascript/styles/mastodon/components.scss

@@ -7863,8 +7863,13 @@ noscript {
         }
       }
 
-      @container account-header (max-width: 372px) {
-        .optional {
+      .optional {
+        @container account-header (max-width: 372px) {
+          display: none;
+        }
+
+        // Fallback for older browsers with no container queries support
+        @media screen and (max-width: 372px + 55px) {
           display: none;
         }
       }