[unified-consent] Fix a11y label for Google services expand button

This fixes the a11y label for the "Other Google services"
expand button on the syncSetup settings page.

Bug: 853996
Change-Id: Ib7dc0b0ce02ab26417553e9b6204b7f4e121a4a9
Reviewed-on: https://chromium-review.googlesource.com/1197822Reviewed-by: Scott Chen <scottchen@chromium.org>
Commit-Queue: Thomas Tangl <tangltom@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587825}

chrome/browser/resources/settings/people_page/sync_page.html

@@ -502,7 +502,7 @@
           </div>
         </div>
         <cr-expand-button expanded="{{personalizeSectionOpened_}}"
-            alt="$i18n{syncExpandA11yLabel}">
+            alt="$i18n{nonPersonalizedServicesExpandA11yLabel}">
         </cr-expand-button>
       </div>
       <iron-collapse id="personalize-section"