api: Add video chat config in initial_snapshot

Added configuration for realmJitsiServerUrl and
realmVideoChatProvider

Author: MritunjayTiwari14

lib/api/model/initial_snapshot.dart

@@ -88,6 +88,10 @@ class InitialSnapshot {
   /// Search for "realm_wildcard_mention_policy" in https://zulip.com/api/register-queue.
   final RealmWildcardMentionPolicy realmWildcardMentionPolicy;
 
+  final String? realmJitsiServerUrl;
+
+  final int realmVideoChatProvider;
+
   final bool realmMandatoryTopics;
 
   final String realmName;
@@ -181,6 +185,8 @@ class InitialSnapshot {
     required this.realmDeleteOwnMessagePolicy,
     required this.realmWildcardMentionPolicy,
     required this.realmMandatoryTopics,
+    required this.realmJitsiServerUrl,
+    required this.realmVideoChatProvider,
     required this.realmName,
     required this.realmWaitingPeriodThreshold,
     required this.realmMessageContentDeleteLimitSeconds,