chore: Unleash AI chat UX bug fixes (#8488)

https://linear.app/unleash/issue/2-2859/small-ux-bug-fixes-on-the-unleash-ai-chat

Bug fixes:

- Up and down arrow keys not functioning in multiline input
- Multiline input expanding beyond the intended size limit
- Chat window failing to properly scroll to the bottom when opened

frontend/src/component/ai/AIChat.tsx

@@ -107,7 +107,9 @@ export const AIChat = () => {
     };
 
     useEffect(() => {
-        scrollToEnd();
+        requestAnimationFrame(() => {
+            scrollToEnd();
+        });
 
         const intersectionObserver = new IntersectionObserver(
             ([entry]) => {

frontend/src/component/ai/AIChatInput.tsx

@@ -81,10 +81,11 @@ export const AIChatInput = ({
                 placeholder='Type your message here'
                 fullWidth
                 multiline
-                maxRows={20}
+                maxRows={5}
                 value={message}
                 onChange={(e) => setMessage(e.target.value)}
                 onKeyDown={(e) => {
+                    e.stopPropagation();
                     if (e.key === 'Enter' && !e.shiftKey) {
                         e.preventDefault();
                         send();