[Cashtab] [deprecate etoken addresses p2] Remove type-specific address descriptors from placeholders and error msgs

Summary:
T2802

Depends on D12677

Remove type-specific address labels and validation errors

Test Plan:
npm start
Check placeholders on Send and SendToken screens
Check placeholder on Send XEC one to many screen
Check validation messages

Reviewers: #bitcoin_abc, kieran709

Reviewed By: #bitcoin_abc, kieran709

Differential Revision: https://reviews.bitcoinabc.org/D12679