There seems to be a miscommunication with regards to this query. You can allow the one-time permission as it has nothing to do with the 30 Day Challenge refund. If you have requested Fyers API for Algo trading, only then you'll not be eligible for the brokerage refund. However, in this case, you can grant the permission and still get the brokerage refund on winning the 30 Day Challenge.
Hope this clarifies!