client/views: fix middle click prevention on buttons for modern browsers

Browsers no longer fire the primary 'click' event for middle clicks.
Old way kept for compatibility as it doesn't hurt anything. All browsers
that support auxclick also have standardized MouseEvent.button values.

client/js/util/views.js

@@ -571,6 +571,11 @@ document.addEventListener("click", (e) => {
         e.preventDefault();
     }
 });
+document.addEventListener("auxclick", (e) => {
+    if (e.target.getAttribute("href") === "" && e.button === 1) {
+        e.preventDefault();
+    }
+});
 
 module.exports = {
     htmlToDom: htmlToDom,