Warn if callbacks are created outside of transactions

[berzanorg]

Currently, when a callback is created outside of a transaction, it neither throws nor warns the developer by an Eslint rule.
There isn't a runtime error while doing so, but as the callback doesn't work as expected it breaks the logic.
And developers see a completely unrelated error message which is unrelated to callbacks because the logic is not working as expected.
I don't know if there is a use case for callbacks to be created outside of transactions.
If there is none, I recommend adding an Eslint rule to warn users when callbacks are created outside of transactions.
If anyone can tell me where and how can I contribute to official o1js Eslint plugin, then I'll gladly do it.

This doesn't work as expected. (as the callback is created outside)

const callback = Experimental.Callback.create(zkAppB, 'approveSend', [amount])

const tx = await Mina.transaction(feePayerAddress, () => {
    AccountUpdate.fundNewAccount(feePayerAddress)
    token.transfer(exchangeAddress, tokenAccount1, amount, callback)
})

But this works.

const tx = await Mina.transaction(feePayerAddress, () => {
    const callback = Experimental.Callback.create(zkAppB, 'approveSend', [amount])
    AccountUpdate.fundNewAccount(feePayerAddress)
    token.transfer(exchangeAddress, tokenAccount1, amount, callback)
})

[mitschabaude]

Thanks for raising this. This could be fixed I think, by running the Callback lazily. But it would be just another instance of internal complication to support magical APIs, which I think we should stop doing.

I'm on the side that we should probably remove Callback. It's a trivial wrapper around running the callback method, and passing the account update that it created on to the other method. That's a much less magical way to think about it, and the behaviour of having to do it in your transaction is more obvious