[MM-62293]: Remove Elasticsearch from translation strings (#29728)

We cannot simply use Elasticsearch any more because
we support Opensearch as well.

Therefore changing Elasticsearch to just say Search.

Note: There are still some cases where Elasticsearch
is used. That is intentional and necessary.

```release-note
NONE
```

server/enterprise/elasticsearch/elasticsearch/elasticsearch.go

@@ -1323,7 +1323,7 @@ func (es *ElasticsearchInterfaceImpl) PurgeIndexes(rctx request.CTX) *model.AppE
 	_, err := es.client.Indices.Delete(indexesToDelete).Do(ctx)
 	if err != nil {
 		rctx.Logger().Error("Elastic Search PurgeIndexes Error", mlog.Err(err))
-		return model.NewAppError("Elasticsearch.PurgeIndexes", "ent.elasticsearch.purge_indexes.delete_failed", nil, "", http.StatusInternalServerError).Wrap(err)
+		return model.NewAppError("Elasticsearch.PurgeIndexes", "ent.elasticsearch.purge_index.delete_failed", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
 
 	return nil

server/enterprise/elasticsearch/opensearch/opensearch.go

@@ -1435,7 +1435,7 @@ func (os *OpensearchInterfaceImpl) PurgeIndexes(rctx request.CTX) *model.AppErro
 	})
 	if err != nil {
 		rctx.Logger().Error("Opensearch PurgeIndexes Error", mlog.Err(err))
-		return model.NewAppError("Opensearch.PurgeIndexes", "ent.elasticsearch.purge_indexes.delete_failed", nil, "", http.StatusInternalServerError).Wrap(err)
+		return model.NewAppError("Opensearch.PurgeIndexes", "ent.elasticsearch.purge_index.delete_failed", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
 
 	return nil