Send and process 'recipient update' sync messages.

SignalServiceKit/src/Messages/OWSMessageSender.m

@@ -1396,15 +1396,9 @@ NSString *const OWSMessageSenderRateLimitedException = @"RateLimitedException";
     if (message.hasSyncedTranscript) {
         shouldSendTranscript = YES;
     } else if (AreRecipientUpdatesEnabled()) {
-        __block BOOL isGroupThread = NO;
-        [self.dbConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
-            isGroupThread = [message threadWithTransaction:transaction].isGroupThread;
-        }];
-        if (isGroupThread) {
         shouldSendTranscript = YES;
         isRecipientUpdate = YES;
     }
-    }
 
     if (!shouldSendTranscript) {
         return success();