Event subscriber persistency: Fix restoring subscribers

Subscriber list is restored only when some of the
parameters are saved as per current implementation
They included parameters which are not mandatory

This commit removed the below attributes
1. registryPrefixes
2. registryMsgIds
3. customText
Retains only attributes which are required as per schema

Tested by:
1. Create subscription and restart BMC
   Verify the subscriptions are persisted

Signed-off-by: Sunitha Harish <sunharis@in.ibm.com>
Change-Id: I52414b0ccf5ae282ce3485dd49e1ae1b7011fdf4
diff --git a/include/event_service_store.hpp b/include/event_service_store.hpp
index d51adad..b04fe0c 100644
--- a/include/event_service_store.hpp
+++ b/include/event_service_store.hpp
@@ -180,11 +180,9 @@
 
         if ((subvalue->id.empty() && !loadFromOldConfig) ||
             subvalue->destinationUrl.empty() || subvalue->protocol.empty() ||
-            subvalue->retryPolicy.empty() || subvalue->customText.empty() ||
+            subvalue->retryPolicy.empty() ||
             subvalue->eventFormatType.empty() ||
-            subvalue->subscriptionType.empty() ||
-            (subvalue->registryPrefixes.empty() &&
-             subvalue->registryMsgIds.empty()))
+            subvalue->subscriptionType.empty())
         {
             BMCWEB_LOG_ERROR << "Subscription missing required field "
                                 "information, refusing to restore";