fix jvm metrics scraper test

Author: laurit

jmx-scraper/src/integrationTest/java/io/opentelemetry/contrib/jmxscraper/target_systems/JvmIntegrationTest.java

@@ -32,12 +32,12 @@ protected JmxScraperContainer customizeScraperContainer(
       JmxScraperContainer scraper, GenericContainer<?> target, Path tempDir) {
     return scraper
         .withTargetSystem("jvm")
-        // TODO when JVM metrics will be added to instrumentation, the default "auto" source
+        // Since JVM metrics were be added to instrumentation, the default "auto" source
         // means that the definitions in instrumentation will be used, and thus this test will fail
         // due to metrics differences, adding an explicit "legacy" source is required to continue
         // testing the JVM metrics defined in this project.
         // https://github.com/open-telemetry/opentelemetry-java-instrumentation/pull/13392
-        // .withTargetSystem("legacy")
+        .withTargetSystemSource("legacy")
         // also testing custom yaml
         .withCustomYaml("custom-metrics.yaml");
   }