MD Settings: Internet: Add/fix remaining policy items

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_DETAILED_BUILD_INFO" desc="Label describing the section that shows detailed information about the current Chrome build.">
       Detailed build information
     </message>
     <message name="IDS_SETTINGS_ABOUT_PAGE_ARC_VERSION" desc="Label for ARC version">
       ARC Version
@@ skipping 1005 matching lines @@
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_SECTION_PROXY" desc="Settings > Internet > Network details: Proxy section label.">
       Proxy
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_SECTION_WPAD" desc="Settings > Internet > Network details: Web Proxy Auto Discovery (WPAD) section label.">
       Web Proxy Auto Discovery URL:
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_SHARED" desc="Settings > Internet > Network details: Text to show when a network is shared.">
       This network is shared with other users.
     </message>
-    <message name="IDS_SETTINGS_INTERNET_NETWORK_PROXY_CONTROLLED_EXTENSION" desc="Settings > Internet > Network details: Text to show when a network proxy is controlled by an extension.">
-      The network proxy is controlled by an extension.
-    </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_PROXY_ENFORCED_POLICY" desc="Settings > Internet > Network details: Text to show when a network proxy is policy enforced.">
       This proxy is enforced by your administrator.
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_PROXY_ALLOW_SHARED" desc="Settings > Internet > Network details: Text next to the checkbox for allowing proxy settings for shared networks.">
       Allow proxies for shared networks
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_PROXY_ALLOW_SHARED_WARNING_TITLE" desc="Settings > Internet > Network details: Title for warning dialog when changing the allow shared proxies setting.">
       Confirm change to allow proxies for shared networks
     </message>
     <message name="IDS_SETTINGS_INTERNET_NETWORK_PROXY_ALLOW_SHARED_WARNING_MESSAGE" desc="Settings > Internet > Network details: Warning message when changing the allow shared proxies setting.">
@@ skipping 1657 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>