Fix: tests

[RaulTrombin]

The current 'make test' encounters some errors during execution.

The first commit addresses only the clippy warnings.

The second commit, fix: Fix test, extract response on client error, resolves the following error:

error[E0599]: no method named `into_inner` found for associated type `<C as ApiClient>::Response` in the current scope
  --> ./cli.rs:74:49
   |
74 |         Err(ApiError::Failure(_, _, r)) => Ok(r.into_inner()),
   |                                                 ^^^^^^^^^^ method not found in `<C as ApiClient>::Response`

Could someone confirm if this commit is the aproach to resolve the issue?

[tiagolobocastro]

Let's keep default as is for now to avoid bumping msrv?

[tiagolobocastro]

Or maybe it's a good time to bump it, though we'd need to have another breaking release but that's ok I guess