3486166-pass-metric-type | Add support for vector search time metric selection

Change to SearchApiAiBackend::doSearch() to include the metric type in active config to the vdb provider vectorSearch() method.

Update AiVdbProviderInterface::vectorSearch() to accept VdbSimilarityMetrics $metric_type as a param. This will require that implementing providers update their vectorSearch method signatures.

[3486166-pass-metric-type]

Closes #3486166

modules/ai_search/src/Plugin/search_api/backend/SearchApiAiSearchBackend.php

@@ -481,6 +481,7 @@ class SearchApiAiSearchBackend extends AiSearchBackendPluginBase implements Plug
         $input = new EmbeddingsInput($search_words);
         $params['vector_input'] = $embedding_llm->embeddings($input, $model_id)->getNormalized();
       }
+      $params['query'] = $query;
       $response = $this->getClient()->vectorSearch(...$params);
     }
     else {