feat(elasticsearch): re-introduce v7 support

Author: Frank Verschuren

src/Symfony/Bundle/DependencyInjection/Configuration.php

@@ -469,9 +469,9 @@ private function addElasticsearchSection(ArrayNodeDefinition $rootNode): void
                                 ->ifTrue()
                                 ->then(static function (bool $v): bool {
                                     if (
-                                        // ES v8 and up
-                                        !class_exists(\Elasticsearch\Client::class)
                                         // ES v7
+                                        !class_exists(\Elasticsearch\Client::class)
+                                        // ES v8 and up
                                         && !class_exists(\Elastic\Elasticsearch\Client::class)
                                     ) {
                                         throw new InvalidConfigurationException('The elasticsearch/elasticsearch package is required for Elasticsearch support.');