Rename buttons for voice interaction value prop screen

chrome/browser/resources/chromeos/login/oobe_voice_interaction_value_prop.css

 /* Copyright 2017 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file. */
 
 #value-prop-view {
   display: block;
   height: 372px;
   margin: auto;
   padding: 0;
 }
 
 .value-prop-loading #retry-button,
-.value-prop-loading #skip-button,
 .value-prop-loaded #retry-button,
-.value-prop-loaded #skip-button,
-.value-prop-error #continue-button,
-.value-prop-error #no-thanks-button {
+.value-prop-error #next-button {
   display: none;
 }
 
 #loading-container,
 #error-container,
 #view-container {
   position: absolute;
   visibility: hidden;
   width: 480px;
 }
 
 .value-prop-loading-animation #loading-container,
 .value-prop-loaded #view-container,
 .value-prop-error #error-container {
   visibility: visible;
 }
 
 .value-prop-loading #retry-button,
-.value-prop-loading #skip-button,
-.value-prop-loading #continue-button,
-.value-prop-loading #no-thanks-button {
+.value-prop-loading #next-button,
+.value-prop-loading #skip-button {
   pointer-events: none;
 }
 
 .title {
   font-size: 18px;
 }
 
 #subtitle {
   font-size: 12px;
   padding: 14px 0 0 0;
@@ skipping 13 matching lines @@
   display: block;
   height: 3px;
   padding: 4px 0 0 0;
   width: 100%;
 }
 
 #skip-button {
   color: rgb(66, 133, 244);
 }
 
-#no-thanks-button {
-  color: rgb(66, 133, 244);
-}
-
 #retry-button {
   -webkit-margin-end: 18px;
 }
 
-#continue-button {
+#next-button {
   -webkit-margin-end: 18px;
 }