Don't return when @PluginFactory is present

This a workaround for apache/logging-log4j2#3126.

Author: ppkarwasz

log4j-converter-plugin-descriptor/src/main/java/org/apache/logging/log4j/converter/plugins/internal/PluginDescriptors.java

@@ -409,8 +409,8 @@ private List<String> findBuilderClassHierarchy(final ClassLoader classLoader) {
                     for (final Annotation annotation : method.getAnnotations()) {
                         switch (annotation.annotationType().getName()) {
                             case PLUGIN_FACTORY:
-                                // No need to search further, there is no builder
-                                return Collections.emptyList();
+                                // Continue the search until apache/logging-log4j2#3126 is fixed.
+                                break;
                             case PLUGIN_BUILDER_FACTORY:
                                 return computeClassHierarchy(findBuilderClass(method.getGenericReturnType()));
                         }