Fix actuator path filter in http traces view while having a

spring-boot-admin-server-ui/src/main/frontend/views/instances/httptrace/index.vue

@@ -164,7 +164,7 @@
         if (this.instance.registration.managementUrl.includes(this.instance.registration.serviceUrl)) {
           const appendix = this.instance.registration.managementUrl.substring(this.instance.registration.serviceUrl.length);
           if (appendix.length > 0) {
-            return `/${appendix}`;
+            return appendix.startsWith('/') ? appendix : `/${appendix}`;
           }
         }
         return null;