[profile picker] Cleanup: remove unused CSS classes in signin promo

This CL removes the classes "fade-in" and "action-link" from the buttons
in the signin promo. These classes are not defined in this scope and
have no effect.

Bug: None
Change-Id: I939e0fbe3392b2f8f2fac86edd68906bb2e961df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567773Reviewed-by: Alex Ilin <alexilin@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832383}

chrome/browser/resources/signin/profile_picker/profile_creation_flow/profile_type_choice.html

@@ -62,12 +62,12 @@
   <h3>$i18n{profileTypeChoiceSubtitle}</h3>
 </div>
 <div id="actionContainer">
-  <cr-button id="signInButton" class="action-button fade-in"
-      on-click="onSignInClick_" disabled="[[loadSigninInProgess_]]">
+  <cr-button id="signInButton" class="action-button" on-click="onSignInClick_"
+      disabled="[[loadSigninInProgess_]]">
     $i18n{signInButtonLabel}
   </cr-button>
-  <button id="notNowButton" class="action-link fade-in"
-      on-click="onNotNowClick_" disabled="[[loadSigninInProgess_]]">
+  <button id="notNowButton" on-click="onNotNowClick_"
+      disabled="[[loadSigninInProgess_]]">
     $i18n{notNowButtonLabel}
   </button>
 </div>