emit data.download event if someone clicks the download link

lib/blocks/GetTheData.svelte

@@ -1,9 +1,16 @@
 <script>
     // external props
+    import PostEvent from '@datawrapper/shared/postEvent';
+
     export let props;
     const { get, __, purifyHtml } = props;
     $: ({ chart, theme } = props);
 
+    function onDownload() {
+        const postEvent = PostEvent(chart.id);
+        postEvent('data.download');
+    }
+
     // internal props
     $: getTheData = get(theme, 'data.options.footer.getTheData', { enabled: false });
 </script>
@@ -12,6 +19,7 @@
     <a
         class="dw-data-link"
         aria-label="{__(getTheData.caption)}: {purifyHtml(chart.title, '')}"
+        on:click={onDownload}
         href="data">
         {__(getTheData.caption)}
     </a>