Update curl example to use x-secret-key header

Replaces the 'x-client-id' header with 'x-secret-key' in the curl example for contract read API, ensuring the correct authentication method is demonstrated.

Author: 0xFirekeeper

apps/dashboard/src/@/components/contracts/code-overview.tsx

@@ -361,7 +361,7 @@ const data = await response.json();`,
     read: `curl https://api.thirdweb.com/v1/contracts/read \\
   --request POST \\
   --header 'Content-Type: application/json' \\
-  --header 'x-client-id: <YOUR_CLIENT_ID>' \\
+  --header 'x-secret-key: <YOUR_SECRET_KEY>' \\
   --data '{
   "calls": [
     {