Fix a few notices

lib/helpers/events_helper.dart

@@ -122,9 +122,7 @@ class NewCallSignalEvent {
     required this.peerID,
     this.sessionDescription,
     this.candidate,
-  })  : assert(callID != null),
-        assert(peerID != null),
-        assert(sessionDescription != null || candidate != null);
+  }) : assert(sessionDescription != null || candidate != null);
 }
 
 /// Call peer ready event

lib/helpers/groups_helper.dart

@@ -51,7 +51,7 @@ class GetAdvancedInfoResult {
   final GetAdvancedInfoStatus status;
   final AdvancedGroupInfo? info;
 
-  GetAdvancedInfoResult(this.status, this.info) : assert(status != null);
+  GetAdvancedInfoResult(this.status, this.info);
 }
 
 /// Groups helper

lib/helpers/serialization/conversation_message_serialization_helper.dart

@@ -15,8 +15,7 @@ class ConversationsMessagesSerializationHelper
   final int convID;
 
   ConversationsMessagesSerializationHelper._(int convID)
-      : convID = convID,
-        assert(convID != null);
+      : convID = convID;
 
   factory ConversationsMessagesSerializationHelper(int? convID) {
     if (_instances == null) _instances = HashMap();

lib/helpers/survey_helper.dart

@@ -26,8 +26,6 @@ class SurveyHelper {
   /// Send the response of a user to a survey
   Future<bool> respondToSurvey(
       {required Survey survey, required SurveyChoice choice}) async {
-    assert(survey != null);
-    assert(choice != null);
 
     return (await APIRequest(
       uri: "surveys/send_response",

lib/helpers/virtual_directory_helper.dart

@@ -13,7 +13,7 @@ class VirtualDirectoryResult {
   const VirtualDirectoryResult({
     required this.type,
     this.id,
-  }) : assert(type != null);
+  });
 }
 
 class VirtualDirectoryHelper {