[ecashaddrjs] Move linting to monorepo standard

Summary:
T2848

Depends on D13386

Remove package-specific linting as the repo is covered by arc lint. arc lint changes required to push the repo to the monorepo break the unit tests. This diff fixes them.

Test Plan: npm test and all pass

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13387