unlinkAuth method is used to remove the linking of a specific smart contract action to an account permission. It returns an Action instance that can then be signed and executed on-chain using the
SessionKit Transact method.
unlinkAuth method is available on any Account instance. Here is an example of how to use it:
const action = testAccount.unlinkAuth("eosio", "claimrewards")
In the example above, we created an action that removes the link between the
claimrewards action and any account permission.
contract: The smart contract account that the action is deployed to.
actionName: The name of the action.