Avoid potential NPE in Metrics filter

The NPE could happen if an exception was thrown
in a ContainerRequestFilter

Fixes: quarkusio#16620

extensions/smallrye-metrics/runtime/src/main/java/io/quarkus/smallrye/metrics/runtime/QuarkusRestMetricsFilter.java

@@ -17,6 +17,9 @@ public class QuarkusRestMetricsFilter {
 
     @ServerResponseFilter
     public void filter(ResourceInfo resourceInfo, Throwable throwable) {
+        if (resourceInfo == null) { // can happen if an exception was thrown before a target method has been identified
+            return;
+        }
         final Class<?> resourceClass = resourceInfo.getResourceClass();
         final Method resourceMethod = resourceInfo.getResourceMethod();
         maybeCreateMetrics(resourceClass, resourceMethod);