[Cashtab] Match transaction input sequence to node and ElectrumABC

Summary:
T2925

Match Cashtab txs sequence number for inputs to eCash node and ElectrumABC.

Note: this will be implemented by default in the Bitgo utxo-lib transaction builder after that is implemented. For now, just overwrite the existing default in functions.

Test Plan:
npm start
Send every kind of tx
Inspect for "sequence": 4294967294 in the JSON tab at https://explorer.bitcoinabc.org/

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D13026