Fix Print Preview sidebar outline

The scroller is now focusable due to Blink changes at r608013.
Remove the outline and take it out of the tab order.

Bug: 905604
Change-Id: Ib8154c691e1240b27118288950c8efdf46c803b6
Reviewed-on: https://chromium-review.googlesource.com/c/1343285Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609495}

chrome/browser/resources/print_preview/new/app.html

@@ -66,6 +66,7 @@
       #container {
         color: var(--google-grey-900);
         flex: 1;
+        outline: none;
         overflow: overlay;
         padding-bottom: 16px;
       }
@@ -94,7 +95,7 @@
           on-print-requested="onPrintRequested_"
           on-cancel-requested="onCancelRequested_">
       </print-preview-header>
-      <div id="container">
+      <div id="container" tabindex="-1">
         <print-preview-destination-settings id="destinationSettings"
             destination="[[destination_]]"
             destination-store="[[destinationStore_]]"