Cleanup: Remove an unused ash string.

ash/ash_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!--
 This file contains the strings for ash.
 -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/ash_strings.h" type="rc_header">
@@ skipping 274 matching lines @@
       <message name="IDS_ASH_STATUS_TRAY_BLUETOOTH_DISCOVERING" desc="The label used in the tray popup to show bluetooth is discovering devices.">
         Scanning for devices...
       </message>
       <message name="IDS_ASH_STATUS_TRAY_TRACING" desc="The status tray item indicating that performance tracing is running.">
         Performance tracing enabled
       </message>
 
       <message name="IDS_ASH_STATUS_TRAY_UPDATE" desc="The label used in the tray popup to notify that the user should restart to get system updates.">
         Restart to update
       </message>
-      <message name="IDS_ASH_STATUS_TRAY_RESTART_AND_POWERWASH_UPDATE" desc="The label used in the tray popup to notify that the user should restart and powerwash to get system updates.">
-        Restart and Powerwash to update
-      </message>
 
       <message name="IDS_ASH_STATUS_TRAY_BRIGHTNESS" desc="The accessible text for the brightness slider.">
         Brightness
       </message>
       <message name="IDS_ASH_STATUS_TRAY_VOLUME" desc="The accessible text for the volume slider.">
         Volume
       </message>
       <message name="IDS_ASH_STATUS_TRAY_AUDIO" desc="The label used in audio detailed page bottom header of ash tray pop up.">
         Audio Settings
       </message>
@@ skipping 292 matching lines @@
 
       <!-- ChromeOS-specific strings -->
       <if expr="pp_ifdef('chromeos')">
         <part file="ash_chromeos_strings.grdp" />
       </if>
 
     </messages>
   </release>
 </grit>