What should you do with your original GTC “take profit” order after legging into an iron condor?

After you leg into an iron condor to adjust say, a bull put spread, by adding a bear call spread - you can leave your original GTC take profit order for the bull put spread intact. If it fills great, if it doesn't, you keep monitoring it as you would any other spread trade (i.e. if the underlying is close to the short strike, you get out shortly before expiry in order to mitigate assignment risk).

As for the bear call spread that you added as an adjustment, the intention is to hold that til expiry and collect the max credit on it. Because if the underlying is indeed challenging your bull put spread, then your bear call spread should expire OTM at max profit.