DynamicGrid: Ensure grid and overlay matches always

In case there are less rows than sidebar entries, the grids
do not match and hence the minimum must be the amount of
sidebar entries that already applies in case the overlay
is empty.

Author: nilmerg

library/Notifications/Widget/TimeGrid/DynamicGrid.php

@@ -129,7 +129,7 @@ protected function assemble()
         ]);
 
         $overlay = $this->createGridOverlay();
-        if ($overlay->isEmpty()) {
+        if ($overlay->isEmpty() || count($overlay) < count($this->sideBar())) {
             $this->style->addFor($this, [
                 '--primaryRows' => count($this->sideBar())
             ]);