web3.js: Make confirmTransaction cancellable

[steveluscher]

Problem

We're about to add a really long running confirmation strategy for transactions in #25303. It's possible for those never to expire and also never be confirmed.

You could conceive of an app that subscribes to this confirmation, but then stops caring if the user navigates away or otherwise becomes disinterested in the status of that transaction. We need to offer a way to signal to confirmTransaction to stop working.

Proposed Solution

1. Make confirmTransaction take an AbortController as an argument
2. Stop work in that function when the abort signal is triggered on it.

[steveluscher]

cc/ @lorisleiva for interest's sake.