Reformat offline summary message on mobile.

BUG=452727

Review URL: https://codereview.chromium.org/882813006

Cr-Commit-Position: refs/heads/master@{#314261}

chrome/app/generated_resources.grd

@@ -9132,9 +9132,7 @@ I don't think this site should be blocked!
         </message>
 
         <message name="IDS_ERRORPAGES_SUMMARY_INTERNET_DISCONNECTED" desc="Mobile: Summary of the error page when the network connection failed.  May be followed by platform dependent instructions.">
-          Wi-Fi and mobile data are turned off.
-          <ph name="LINE_BREAK">&lt;br /&gt;&lt;br /&gt;<ex>&lt;br /&gt;&lt;br /&gt;</ex></ph>
-          The page can be loaded once you connect to a network.
+          Wi-Fi and mobile data are turned off. The page can be loaded once you connect to a network.
         </message>
       </if>
       <if expr="not is_android and not is_ios">