Add missing policies to to device policy proto

The |report_session_status| and |device_status_frequency| policies
were added on the server side in violation of our protocol:
Policies must always be added to the client-side proto first and
synced to the server.

In general, new policies should be added to the device policy proto
and policy_templates.json at the same time. As an emergency fix, this
CL gets a free pass for that rule as it is an emergency fix.

BUG=430908
TEST=None

Review URL: https://codereview.chromium.org/891323002

Cr-Commit-Position: refs/heads/master@{#314347}

chrome/browser/chromeos/policy/proto/chrome_device_policy.proto

@@ -98,6 +98,10 @@ message DeviceReportingProto {
   optional bool report_network_interfaces = 5;
   optional bool report_users = 6;
   optional bool report_hardware_status = 7;
+  optional bool report_session_status = 8 [default = true];
+
+  // Frequency to report device status, default to 3 hours.
+  optional int64 device_status_frequency = 9 [default = 10800000];
 }
 
 message EphemeralUsersEnabledProto {