[Profiles]: Add default avatar label.

Bug: 1147088
Change-Id: Iab848975d1c1b905b158d6572337d27286a377bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537672
Commit-Queue: Monica Basta <msalama@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Auto-Submit: Monica Basta <msalama@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827232}

chrome/app/profiles_strings.grdp

@@ -348,6 +348,9 @@
   <message name="IDS_DEFAULT_AVATAR_LABEL_25" desc="The label for the sun and cloud avatar.">
     Sun and clouds
   </message>
+  <message name="IDS_DEFAULT_AVATAR_LABEL_26" desc="The label for the default avatar.">
+    Default avatar
+  </message>
   <message name="IDS_DEFAULT_AVATAR_LABEL_27" desc="The label for the cat avatar.">
     Cat
   </message>

chrome/app/profiles_strings_grdp/IDS_DEFAULT_AVATAR_LABEL_26.png.sha1

+defb7ccbaa8862efbcb42239ea144482bdc58789
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