feat: read PeriodicInformInterval and PeriodicInformEnable in critical reads

Add Device.ManagementServer.PeriodicInformInterval and
Device.ManagementServer.PeriodicInformEnable to the GPV performed
during CriticalReadsState (applies to both TR-181 and TR-098).

app/services/cwmp/main_state_machine.ts

@@ -227,6 +227,8 @@ class CriticalReadsState extends DeviceState {
         `${root}.DeviceInfo.SoftwareVersion`,
         `${root}.DeviceInfo.ModelName`,
         `${root}.ManagementServer.ConnectionRequestURL`,
+        `${root}.ManagementServer.PeriodicInformInterval`,
+        `${root}.ManagementServer.PeriodicInformEnable`,
       ]
 
       const response = await context.services.deviceAction.getParameterValues(