isolateserver: add checkbox to enable ts_mon

appengine/isolate/handlers_frontend.py

Index: appengine/isolate/handlers_frontend.py
diff --git a/appengine/isolate/handlers_frontend.py b/appengine/isolate/handlers_frontend.py
index f93736c7497398d8b6f43ad7920c01cc3040c283..5ef2947022184392b74d41e2235b1e44fe2bb959 100644
--- a/appengine/isolate/handlers_frontend.py
+++ b/appengine/isolate/handlers_frontend.py
@@ -67,7 +67,8 @@ class RestrictedConfigHandler(auth.AuthenticatingHandler):
   def post(self):
     # Convert MultiDict into a dict.
     params = {
-      k: self.request.params.getone(k) for k in self.request.params
+      k: config.GlobalConfig.cast_to_type(k, self.request.params.getone(k))
+      for k in self.request.params
       if k not in ('keyid', 'xsrf_token')
     }
     cfg = config.settings(fresh=True)