Add EAP notice for model configuration (#597)

-
https://sourcegraph.slack.com/archives/C05A5R7NQUX/p1724282914231849?thread_ts=1724221561.516719&cid=C05A5R7NQUX

Author: MaedahBatool

docs/cody/clients/model-configuration.mdx

@@ -10,6 +10,8 @@ This is accomplished exposing much more flexible configuration options for Cody
 
 ## Quickstart
 
+<Callout type="info">Before you start, please note that the model configuration is an early access program (EAP) and we are working to make the experience better.</Callout> 
+
 The simplest way to configure your Sourcegraph Enterprise would be to add the following configuration section to your instance's [site configuration](/admin/config/site_config):
 
 ```json