fix: correct RSpec expectation syntax in test

- Use have_received instead of receive for post-call verification
- Fixes test failure in config method tracking test

Co-Authored-By: [email protected] <[email protected]>

Author: devin-ai-integration[bot]

spec/server/ai/config_tracker_spec.rb

@@ -393,7 +393,7 @@
 
       client.config('test-config-key', context, default_value)
 
-      expect(ld_client).to receive(:track).with(
+      expect(ld_client).to have_received(:track).with(
         '$ld:ai:config:function:single',
         context,
         'test-config-key',