renewal: use early return for empty lineage server (#10392)

This allows outdenting most of the logic for _ari_renewal_time.

Split from #10377.

certbot/src/certbot/_internal/renewal.py

@@ -337,7 +337,11 @@ def _ari_renewal_time(config: configuration.NamespaceConfig,
     # conf, i.e. `lineage.server`
     #
     # Fixes https://github.com/certbot/certbot/issues/10339
-    if lineage.server:
+    if not lineage.server:
+        renewal_conf_file = storage.renewal_filename_for_lineagename(config, lineage.lineagename)
+        logger.warning("Skipping ARI check because %s has no 'server' field. This issue will not "
+                       "prevent certificate renewal", renewal_conf_file)
+        return None
     try:
         # Creating a new ACME client makes a network request, so check if we have
         # one cached for this cert's server already
@@ -356,10 +360,6 @@ def _ari_renewal_time(config: configuration.NamespaceConfig,
                        "problem persists and you think it's a bug in Certbot, please open an "
                        "issue at https://github.com/certbot/certbot/issues/new/choose.")
         logger.debug("Error while requesting ARI was:", exc_info=True)
-    else:
-        renewal_conf_file = storage.renewal_filename_for_lineagename(config, lineage.lineagename)
-        logger.warning("Skipping ARI check because %s has no 'server' field. This issue will not "
-                       "prevent certificate renewal", renewal_conf_file)
 
     return None