fix(LLMO-4070): guard against null configuration in patchAuditForSite

Configuration.findLatest() returns null when no config exists in S3
(NoSuchKey case). Calling .getHandlers() on null threw a TypeError,
surfacing as a 500 in environments where the config bucket exists but
has no object (IT test VPC environment). Skip the audit-type validation
when no configuration is available — in production the config is always
present.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: noelruiz34

src/controllers/audits.js

@@ -219,10 +219,12 @@ function AuditsController(ctx) {
     }
 
     const configuration = await Configuration.findLatest();
-    const registeredAudits = configuration.getHandlers();
-    if (!registeredAudits[auditType]) {
-      return notFound(`The "${auditType}" is not present in the configuration. List of allowed audits:`
-        + ` ${Object.keys(registeredAudits).join(', ')}.`);
+    if (configuration) {
+      const registeredAudits = configuration.getHandlers();
+      if (!registeredAudits[auditType]) {
+        return notFound(`The "${auditType}" is not present in the configuration. List of allowed audits:`
+          + ` ${Object.keys(registeredAudits).join(', ')}.`);
+      }
     }
 
     const siteConfig = site.getConfig();