[ecash-wallet] Support including arbitrary data with ALP txs

Summary: ALP txs may include arbitary information in addition to the token tx itself. Support this with the already-defined DataAction.

Test Plan: npm test, CI integration test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D18585