Don't sync verification until NullMessage succeeds. This better mirrors

existing sync message behavior

// FREEBIE

src/Messages/OWSIdentityManager.m

@@ -515,12 +515,8 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
                                                                    verificationStateSyncMessage:message];
     [self.messageSender sendMessage:nullMessage
         success:^{
+            dispatch_async(dispatch_get_main_queue(), ^{
                 DDLogInfo(@"%@ Successfully sent verification state NullMessage", self.tag);
-                            }
-                            failure:^(NSError * _Nonnull error) {
-                                DDLogError(@"%@ Failed to send verification state NullMessage with error: %@", self.tag, error);
-                            }];
-    
                 [self.messageSender sendMessage:message
                     success:^{
                         DDLogInfo(@"%@ Successfully sent verification state sync message", self.tag);
@@ -529,7 +525,13 @@ NSString *const kNSNotificationName_IdentityStateDidChange = @"kNSNotificationNa
                         [self clearSyncMessageForRecipientId:message.verificationForRecipientId];
                     }
                     failure:^(NSError *error) {
-            DDLogError(@"%@ Failed to send verification state sync message with error: %@", self.tag, error);
+                        DDLogError(
+                            @"%@ Failed to send verification state sync message with error: %@", self.tag, error);
+                    }];
+            });
+        }
+        failure:^(NSError *_Nonnull error) {
+            DDLogError(@"%@ Failed to send verification state NullMessage with error: %@", self.tag, error);
         }];
 }