[Cashtab] [p3] Patch fee falc in sendToken

Summary:
T2644
Depends on D11925

Test Plan:
At cashtab.com, npm start and send several eToken txs. Eventually you will have one with a dust error
arc patch this diff and send the same tx, confirm no dust error

Reviewers: #bitcoin_abc, kieran709

Reviewed By: #bitcoin_abc, kieran709

Differential Revision: https://reviews.bitcoinabc.org/D11926