Fix class name

Author: manuel-alvarez-alvarez

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/Agent.java

@@ -1094,7 +1094,7 @@ private static void maybeStartFeatureFlag(final Class<?> scoClass, final Object
 
       try {
         final Class<?> ffSysClass =
-            AGENT_CLASSLOADER.loadClass("com.datadog.featureflag.FeatureFlagSystem");
+            AGENT_CLASSLOADER.loadClass("com.datadog.featureflag.FeatureFlaggingSystem");
         final Method ffSysMethod = ffSysClass.getMethod("start", scoClass);
         ffSysMethod.invoke(null, sco);
       } catch (final Throwable e) {