Remove unused string IDS_PLUGIN_VM_INSTALLER_TIME_LEFT_MESSAGE

r754449 removed usage of the aforementioned string but not the string
itself.

Bug: 1041311
Change-Id: I8f4298f974f51839a625393a5fbce25326d36e38
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2149480Reviewed-by: Julian Watson <juwa@google.com>
Commit-Queue: Timothy Loh <timloh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759148}

chrome/app/chromeos_strings.grdp

@@ -4960,9 +4960,6 @@
   <message name="IDS_PLUGIN_VM_INSTALLER_DOWNLOAD_PROGRESS_WITHOUT_DOWNLOAD_SIZE_MESSAGE" desc="Text of the Plugin VM installer while downloading Plugin VM image, showing download progress when the full download size is not known.">
     <ph name="DOWNLOADED_SIZE">$1<ex>1.2 GB</ex></ph>
   </message>
-  <message name="IDS_PLUGIN_VM_INSTALLER_TIME_LEFT_MESSAGE" desc="Text of the Plugin VM installer that shows estimated time left before current installation stage ends.">
-    <ph name="TIME_LEFT">$1<ex>30 mins</ex></ph> left
-  </message>
   <message name="IDS_PLUGIN_VM_INSTALLER_CONTINUE_BUTTON" desc="Label for the button in the Plugin VM installer to continue installation.">
     Continue
   </message>

chrome/app/chromeos_strings_grdp/IDS_PLUGIN_VM_INSTALLER_TIME_LEFT_MESSAGE.png.sha1

-35a7f67d6407ee1a3f9295e6537b569982a3bf82
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