[codex] Fix app-server initialized request analytics build (#17830)

Problem: PR #17372 moved initialized request handling into
`dispatch_initialized_client_request`, leaving analytics code that uses
`connection_id` without a local binding and breaking `codex-app-server`
builds.

Solution: Restore the `connection_id` binding from
`connection_request_id` before initialized request validation and
analytics tracking.

codex-rs/app-server/src/message_processor.rs

@@ -725,6 +725,8 @@ impl MessageProcessor {
         session: Arc<ConnectionSessionState>,
         request_context: RequestContext,
     ) {
+        let connection_id = connection_request_id.connection_id;
+
         if !session.initialized() {
             let error = JSONRPCErrorError {
                 code: INVALID_REQUEST_ERROR_CODE,