[NTP] Hide the Google Photos option

Hide the Google Photos option for custom backgrounds as it will
not be launched in M69.

All service requests occur after clicking on the option, so simply
hiding it is sufficient.

Bug: 869230
Change-Id: I55ca201978323cd7031e618b6a9039b93a485130
Reviewed-on: https://chromium-review.googlesource.com/1155978Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Kyle Milka <kmilka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579309}

chrome/browser/resources/local_ntp/local_ntp.html

@@ -88,7 +88,7 @@
 
   <dialog div id="edit-bg-dialog">
     <div id="edit-bg-title"></div>
-    <div id="edit-bg-google-photos" class="bg-option" tabindex="0">
+    <div id="edit-bg-google-photos" class="bg-option" tabindex="0" hidden>
       <div class="bg-option-img"></div>
       <div id="edit-bg-google-photos-text" class="bg-option-text"></div>
     </div>

chrome/test/data/local_ntp/local_ntp_browsertest.html

@@ -73,7 +73,7 @@
 
     <dialog div id="edit-bg-dialog">
       <div id="edit-bg-title"></div>
-      <div id="edit-bg-google-photos" class="bg-option" tabindex="0">
+      <div id="edit-bg-google-photos" class="bg-option" tabindex="0" hidden>
         <div class="bg-option-img"></div>
         <div id="edit-bg-google-photos-text" class="bg-option-text"></div>
       </div>