ci(atest): Increase retry delay for test server

Increased the retry delay for the test server connection in the CI workflow to improve stability.

.github/workflows/atest.yml

@@ -33,7 +33,7 @@ jobs:
         run: |
           pdm testenv &
           echo "Waiting for test server to become available..."
-          curl --retry 5 --retry-connrefused --retry-delay 2 http://localhost:8273
+          curl --retry 5 --retry-connrefused --retry-delay 3 http://localhost:8273
 
       - name: Run acceptance tests
         run: pdm atest