[CrOS Settings] Clicking terms of service opens ToS in chrome browser.

Before, the terms of service link would cause the OS settings window
to navigate to the ToS page without a back button.

Fixed: 1096892
Change-Id: Ieb8452ad969013e4242b7552d3fb4bcb0daadf5a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2314159Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791965}

chrome/browser/resources/settings/chromeos/os_about_page/os_about_page.html

@@ -207,7 +207,9 @@
         </div>
 <if expr="_google_chrome">
         <div class="secondary">
-          <a href="$i18n{aboutTermsURL}">$i18n{aboutProductTos}</a>
+          <a href="$i18n{aboutTermsURL}" target="_blank">
+            $i18n{aboutProductTos}
+          </a>
         </div>
 </if>
       </div>