Create Print Servers dropdown placeholder string

Bug: b:168650771
Change-Id: Ied905968e428857f3890e4355db65c25b2dde282
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2496000Reviewed-by: Brian Malcolm <bmalcolm@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Matt Menard <mattme@google.com>
Cr-Commit-Position: refs/heads/master@{#821802}

chrome/app/printing_strings.grdp

@@ -302,6 +302,9 @@
       These settings are enforced by your administrator
     </message>
     <if expr="chromeos">
+      <message name="IDS_PRINT_PREVIEW_SERVER_SEARCH_BOX_PLACEHOLDER" desc="Text to put in a print server search box when user has not entered a search query.">
+        Print servers
+      </message>
       <message name="IDS_PRINT_PREVIEW_OPTION_PIN" desc="Option to print with pin.">
         Enable user pin
       </message>

chrome/app/printing_strings_grdp/IDS_PRINT_PREVIEW_SERVER_SEARCH_BOX_PLACEHOLDER.png.sha1

+8c8fef1294c1a36ac4e3d149fa3dc7b90cbc6046
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