Remove Obj-c proto parser.

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -682,16 +682,8 @@ NS_ASSUME_NONNULL_BEGIN
                     }];
             });
         } else if (syncMessage.request.type == SSKProtoSyncMessageRequestTypeGroups) {
-            // We respond asynchronously.
-            //
-            // In rare cases this means we won't respond to the sync request, but that's
-            // acceptable.
-            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
             OWSSyncGroupsMessage *syncGroupsMessage = [[OWSSyncGroupsMessage alloc] init];
-                __block NSData *_Nullable syncData;
-                [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-                    syncData = [syncGroupsMessage buildPlainTextAttachmentDataWithTransaction:transaction];
-                }];
+            NSData *_Nullable syncData = [syncGroupsMessage buildPlainTextAttachmentDataWithTransaction:transaction];
             if (!syncData) {
                 OWSFail(@"%@ Failed to serialize groups sync message.", self.logTag);
                 return;
@@ -706,7 +698,6 @@ NS_ASSUME_NONNULL_BEGIN
                 failure:^(NSError *error) {
                     DDLogError(@"%@ Failed to send Groups response syncMessage with error: %@", self.logTag, error);
                 }];
-            });
         } else if (syncMessage.request.type == SSKProtoSyncMessageRequestTypeBlocked) {
             DDLogInfo(@"%@ Received request for block list", self.logTag);
             [_blockingManager syncBlockedPhoneNumbers];