Add empty test to ESLoggerUsageTests

This commit adds an empty test to ESLoggerUsageTests to avoid the test
suite from failing for having no tests after the existing tests were
marked as awaits fix in 1d197eddcc2a5dea7d7608d76530e1c2b20f2cd0.

test/logger-usage/src/test/java/org/elasticsearch/test/loggerusage/ESLoggerUsageTests.java

@@ -39,6 +39,11 @@ import static org.hamcrest.Matchers.notNullValue;
 
 public class ESLoggerUsageTests extends ESTestCase {
 
+    // needed to avoid the test suite from failing for having no tests
+    public void testSoThatTestsDoNotFail() {
+
+    }
+
     @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/20243")
     public void testLoggerUsageChecks() throws IOException {
         for (Method method : getClass().getMethods()) {