Fixes #7034, correctly compute Referrers distinct metrics by counting array,...

Fixes #7034, correctly compute Referrers distinct metrics by counting array, not DataArray instance (which results in 1 always).

plugins/Referrers/Archiver.php

@@ -204,10 +204,10 @@ class Archiver extends \Piwik\Plugin\Archiver
     protected function insertDayNumericMetrics()
     {
         $numericRecords = array(
-            self::METRIC_DISTINCT_SEARCH_ENGINE_RECORD_NAME => count($this->getDataArray(self::SEARCH_ENGINES_RECORD_NAME)),
-            self::METRIC_DISTINCT_KEYWORD_RECORD_NAME       => count($this->getDataArray(self::KEYWORDS_RECORD_NAME)),
-            self::METRIC_DISTINCT_CAMPAIGN_RECORD_NAME      => count($this->getDataArray(self::CAMPAIGNS_RECORD_NAME)),
-            self::METRIC_DISTINCT_WEBSITE_RECORD_NAME       => count($this->getDataArray(self::WEBSITES_RECORD_NAME)),
+            self::METRIC_DISTINCT_SEARCH_ENGINE_RECORD_NAME => count($this->getDataArray(self::SEARCH_ENGINES_RECORD_NAME)->getDataArray()),
+            self::METRIC_DISTINCT_KEYWORD_RECORD_NAME       => count($this->getDataArray(self::KEYWORDS_RECORD_NAME)->getDataArray()),
+            self::METRIC_DISTINCT_CAMPAIGN_RECORD_NAME      => count($this->getDataArray(self::CAMPAIGNS_RECORD_NAME)->getDataArray()),
+            self::METRIC_DISTINCT_WEBSITE_RECORD_NAME       => count($this->getDataArray(self::WEBSITES_RECORD_NAME)->getDataArray()),
             self::METRIC_DISTINCT_URLS_RECORD_NAME          => count($this->distinctUrls),
         );