Cleanup: Remove unused strings related to the about page.

chrome/app/resources/locale_settings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/locale_settings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="locale_settings_am.pak" type="data_package" lang="am" />
     <output filename="locale_settings_ar.pak" type="data_package" lang="ar" />
     <if expr="pp_ifdef('use_third_party_translations')">
       <output filename="locale_settings_ast.pak" type="data_package" lang="ast" />
@@ skipping 222 matching lines @@
       <!-- The default value for |WebPreference::uses_universal_detector|. -->
       <message name="IDS_USES_UNIVERSAL_DETECTOR" use_name_for_id="true">
         false
       </message>
 
       <!-- The file name of the spellchecking dictionary without the extension (case-sensitive). -->
       <message name="IDS_SPELLCHECK_DICTIONARY" use_name_for_id="true">
         en-US
       </message>
 
-      <!-- The width and height of the About dialog box in characters and lines (See -->
-      <!-- above). -->
-      <message name="IDS_ABOUT_DIALOG_WIDTH_CHARS" use_name_for_id="true">
-        86
-      </message>
-      <message name="IDS_ABOUT_DIALOG_MINIMUM_HEIGHT_LINES" use_name_for_id="true">
-        4
-      </message>
-
       <!-- The width of the Crucial Notification bubble in characters (See above). -->
       <message name="IDS_CRUCIAL_NOTIFICATION_BUBBLE_WIDTH_CHARS" use_name_for_id="true">
         55
       </message>
 
       <!-- The width and height of the Join Wi-Fi network dialog box in -->
       <!-- characters and lines (See above). -->
       <message name="IDS_JOIN_WIFI_NETWORK_DIALOG_WIDTH_CHARS" use_name_for_id="true">
         60
       </message>
@@ skipping 200 matching lines @@
         <message name="IDS_PASSWORD_CHANGED_DIALOG_WIDTH_CHARS" use_name_for_id="true">
           70
         </message>
         <message name="IDS_PASSWORD_CHANGED_DIALOG_HEIGHT_LINES" use_name_for_id="true">
           16
         </message>
       </if>
     </messages>
   </release>
 </grit>