OAuth tests cleanup, they don't modify the user's profile anymore

[marioortizmanero]

Description

This PR takes care of the "Authenticated tests should actually not modify the user's account and cause minimal changes (as in, don't completely delete the user's library for a test)." task in #127.

It also includes some fixes so that they work:

• Closes Recommendations endpoint: unknown variant ARTIST, expected one of artist, track, genre #225
• Closes playlist_unfollow, playlist_change_detail take a &str for the Id, but it should be an Id type #227
• Closes playlist_reorder_tracks doesn't need the uris parameter #228
• Closes playlist_unfollow should return ClientResult<()> #229
• Closes Missing resume_playback #231

Dependencies

None

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

cargo test --features=env-file,cli -- --ignored --test-threads=1
cargo test --features=env-file,cli,client-ureq,ureq-rustls-tls --no-default-features -- --ignored --test-threads=1

[marioortizmanero]

@thecakeisalie25, remembering your comment in #154, I've just cleaned up the tests with oauth in this PR and I wouldn't really add them to an automatic flow. It's impossible to fully revert all of the changes the tests may apply (the queue can't be restored, for example), and it's still quite annoying if you're playing music at the same time (some songs play for a fraction of a second, etc). I wouldn't like these things happening whenever a new commit reaches master on my personal account. Or at least in its current state.

Check out these tests and see for yourself.

[marioortizmanero]

As a warning: I'm leaving on a couple weeks of vacation, I'll be back for more stuff!

[marioortizmanero]

I'm back! Is there anything else left in order to merge this?

[ramsayleung]

The CI failed :)

[marioortizmanero]

I have no clue why the tests failed, honestly. I've added the RUST_BACKTRACE=1 env variable so that next time this happens it's caught. But I didn't touch the function which made the tests fail, so it's not related to this PR and it can be merged.