Use `Terminal` to print output instead of `println` in the `secure-channel delete` command

[adrianbenavides]

Current behavior

The secure-channel show command is using println to print the command's output, which is a strategy that is being deprecated.

Desired behavior

Instead, the Terminal struct should be used to handle the output of every command.

Implementation details

The following function should be refactored:

https://github.com/build-trust/ockam/blob/9c49e470a574d91854aa24628584eda4554aaad0/implementations/rust/ockam/ockam_command/src/secure_channel/delete.rs#L49

You have to extract the printed contents into two variables (one for plain and another for json) and use the Terminal` struct as follows to print the command output:

opts.terminal
    .stdout()
    .plain(plain)
    .json(json)
    .write_line()?;

---

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