fix: normalize tag name comparison

Author: gadenbuie

js/markdown-stream/markdown-stream.ts

@@ -284,7 +284,7 @@ class MarkdownElement extends LightElement {
     while (el) {
       if (el.scrollHeight > el.clientHeight) return el;
       el = el.parentElement;
-      if (el?.tagName === CHAT_CONTAINER_TAG) {
+      if (el?.tagName?.toLowerCase() === CHAT_CONTAINER_TAG.toLowerCase()) {
         // This ensures that we do not accidentally scroll a parent element of the chat
         // container. If the chat container itself is scrollable, a scrollable element
         // would already have been identified.