Tests for CLI Command Deploy

### Is your feature request related to a problem?

We should test all the branching of deploy command.

### Describe the solution you'd like

we can leverage
- [ ] mock-stdin
- [ ] mock-websocket
https://github.com/phoenixframework/phoenix/blob/main/assets/test/socket_test.js

### Additional context

_No response_

Start at the CLI's deploy command and review its branching behavior. Use the proposed mock-stdin and mock-websocket approaches, with Phoenix's assets/test/socket_test.js as a reference, and add coverage for all deploy branches; done means the command's branching behavior is exercised by tests.

Written by the indexing model from the issue text.