Hide local host out-of-date warning by default.

This avoids it being visible when the user first runs the app if they are able
to expand the Me2Me section before the XHR to fetch the host list has completed.
Note that they will still see a blank entry in this case, but only if the local
host is registered. Since the name of the local host isn't known until the XHR
returns, there's no easy solution to that, and given how much a corner case it
is, I don't think it's worth fixing.

BUG=277168

Review URL: https://codereview.chromium.org/128323002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243727 0039d316-1c4b-4281-b951-d872f2087c98

remoting/webapp/main.html

@@ -201,7 +201,7 @@ found in the LICENSE file.
                  class="section-row clickable no-non-local-hosts"
                  data-daemon-state="enabled">
               <div class="host-list-main-icon">
-                <span id="this-host-warning"></span>
+                <span id="this-host-warning" hidden></span>
                 <img id="this-host-icon"
                      src="icon_host.webp">
               </div>