Update apps/portal/src/app/ai/chat/migrate-from-nebula/page.mdx

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: samina <[email protected]>

Author: saminacodes

apps/portal/src/app/ai/chat/migrate-from-nebula/page.mdx

@@ -53,7 +53,7 @@ fetch("<https://nebula-api.thirdweb.com/chat>", {
 ## After (thirdweb AI Chat API)
 
 ```typescript
-fetch("<https://api.thirdweb.com/ai/chat>", {
+fetch("https://api.thirdweb.com/ai/chat", {
   method: "POST",
   headers: {
     "Content-Type": "application/json",