[TASK] Log solr response in case of Page indexing issue

Logging the response eases debugging.
Integrators and developers can check the response in order to retrieve
the actual reported issue, a crucial info in order to fix indexing
issues.

By: @DanielSiepmann
Fixes: #3846, #2590

Classes/IndexQueue/FrontendHelper/PageIndexer.php

@@ -349,6 +349,7 @@ protected function addDocumentsToSolrIndex(array $documents): bool
             foreach ($documentChunks as $documentChunk) {
                 $response = $this->solrConnection->getWriteService()->addDocuments($documentChunk);
                 if ($response->getHttpStatus() != 200) {
+                    $this->logger->error('Solr could not index page.', [$response->getRawResponse()]);
                     throw new \RuntimeException('Solr Request failed.', 1331834983);
                 }
             }