Make sure to group the label in Referrer Websites report (#13884)

* Make sure to group the label in Referrer Websites report

I just debugged and can confirm behaviour described in #13882 
The label includes a URL like `http://demo.matomo.org/foo/bar` and the label is then removed in the `ColumnCallbackReplace` filter meaning there could be several entries with the same label and a group by is needed.

* make sure to apply filter before paging

* Add test + slight optimization.

1 files changed, 2 insertions, 3 deletions

diff --git a/plugins/Referrers/DataTable/Filter/UrlsFromWebsiteId.php b/plugins/Referrers/DataTable/Filter/UrlsFromWebsiteId.php
index 56ae1ac792..0a013e031b 100644
--- a/plugins/Referrers/DataTable/Filter/UrlsFromWebsiteId.php
+++ b/plugins/Referrers/DataTable/Filter/UrlsFromWebsiteId.php
@@ -35,8 +35,7 @@ class UrlsFromWebsiteId extends BaseFilter
         $table->filter('ColumnCallbackAddMetadata', array('label', 'url', function ($label) {
             return htmlspecialchars_decode($label);
         }));
-        $table->filter('ColumnCallbackReplace', array('label', 'Piwik\Plugins\Referrers\getPathFromUrl'));
-        $table->filter('GroupBy', array('label'));
+        $table->filter('GroupBy', array('label', 'Piwik\Plugins\Referrers\getPathFromUrl'));
 
         foreach ($table->getRowsWithoutSummaryRow() as $row) {
             $subtable = $row->getSubtable();
@@ -45,4 +44,4 @@ class UrlsFromWebsiteId extends BaseFilter
             }
         }
     }
-}
\ No newline at end of file
+}