OOBE - Improve focus handling on EULA screen

Clicking/Tapping on the 'Learn More' link on the EULA screen will
now change the focus to the link itself.

Fixed: 1025176
Change-Id: I12ce9c5c4d7d07d9634a2bda66f44441b439c7dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1991480
Auto-Submit: Renato Silva <rrsilva@google.com>
Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Commit-Queue: Renato Silva <rrsilva@google.com>
Cr-Commit-Position: refs/heads/master@{#730108}

chrome/browser/resources/chromeos/login/oobe_eula.js

@@ -172,6 +172,7 @@ Polymer({
    * @private
    */
   onUsageStatsHelpLinkClicked_: function(e) {
+    this.$['learn-more'].focus();
     chrome.send('eulaOnLearnMore');
     e.stopPropagation();
   },