[ecash-lib] Patch for nodejs tx building

Summary:
Attempting to accept agora txs generates a crazy rabbit hole of an error that, if followed, will lead you here. This instanceof check fails in nodejs.

Cashtab does this with no problems but nodejs apps can't.

There are probably more issues like this and potentially we need a more general fix. But I am still learning about the issue.

For now, if we know this works and does not break existing use cases, I think we should go with it. The issue is known and improvements can build on this.

Test Plan: CI tests

Reviewers: #bitcoin_abc, tobias_ruck

Reviewed By: #bitcoin_abc, tobias_ruck

Differential Revision: https://reviews.bitcoinabc.org/D17461