[Cashtab] [deprecate BCH from token send p2] Remove from Send, Burn, and SendToken

Summary:
T2730

Depends on D12671

Remove the (now-unused) BCH param from sendToken and burnToken

Because these are the only function that still consume bchObj in SendToken, this diff must also remove it from SendToken screen + snapshots

Test Plan:
npm start
Send an etoken tx
Do an etoken burn tx

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D12690