Abandoning a transaction does not delete it from the wallet. It only lets the wallet know that it can ignore the transaction when constructing new transactions. They remain in the wallet in the event that the transaction is rebroadcast (possibly by someone else) and therefore has the possibility of confirming. They are otherwise okay to leave in the wallet and they can be ignored.
Transactions can be forcibly deleted from the wallet file by using the removeprunedfunds RPC. However, be very careful with this as removing transactions that are still relevant can result in the wallet misbehaving, such as accidentally double spending already spent outputs, or showing and incorrect balance. Only do this if you are sure the transaction is irrelevant (i.e. all outputs already spent, transaction is conflicted, etc.). It is otherwise okay to leave irrelevant transactions in the wallet.
In your case, because the transactions are marked as abandoned, they are not entirely irrelevant. They can still be revived if someone were to broadcast them again. As such, I would advise leaving the transactions alone. You can remove them once they become conflicted. For that to happen, another transaction spending the same inputs needs to become confirmed.
