Bitcoin sent to Bitcoin Cash address, How to Recover?
Unfortunately, once the transaction is confirmed on the blockchain there is no way to retreive the funds and, that I know of, there is no way to zap the pending transaction from the distributed mempool, nor can I imagine a way. The transaction will likely be confirmed in due course.

Even if Blockchain.com zap the tx locally and the Bitcoin show up again in your friends wallet, once the transaction confirms on the blockchain the outputs used to create the transaction will be spent and that Bitcoin will not be spendable. This also protects against double spending.

The one possible solution to this problem is if your friends Blockchain.com wallet allows RBF (replace-by-fee), you could conceivably (and I do not know how granular transaction control is with Blockchain.com) replace the original transaction with a transaction paying instead back to herself and with a higher fee. A few caveats, RBF is opt-in and so would have to be enabled on the original transaction, Blockchain.com needs to have the user functionality necessary to do this and, once the original transaction is confirmed it is game over anyway.