Add eventlistener to enable print button

Author: atishdhu

web/app.js

@@ -2001,6 +2001,12 @@ const PDFViewerApplication = {
         opts
       );
     }
+    window.addEventListener("message", event => {
+      if (event.data.type === "imagedownload") {
+        const printButton = document.getElementById("printButton");
+        printButton?.classList.remove("hidden");
+      }
+    });
   },
 
   bindWindowEvents() {

web/viewer.html

@@ -329,7 +329,7 @@
                   </button>
                 </div>
 
-                <div class="verticalToolbarSeparator hiddenMediumView hidden"></div>
+                <div class="verticalToolbarSeparator hiddenMediumView"></div>
 
                 <div id="secondaryToolbarToggle" class="toolbarButtonWithContainer">
                   <button id="secondaryToolbarToggleButton" class="toolbarButton" type="button" title="Tools" tabindex="0" data-l10n-id="pdfjs-tools-button" aria-expanded="false" aria-haspopup="true" aria-controls="secondaryToolbar">