fix: override oauth2.HTTPClient w/ ctx correctly

[lol768]

Previously, the various commands that exist to help you do the OAuth2 flow locally were not overriding the oauth2.HTTPClient via the context correctly. This meant that if you were e.g. running Hydra locally and using a self-signed/test TLS certificate, the flows would fail with TLS errors even in the presence of the --skip-tls-verify flag.

Steps to reproduce bug:

1. Set SERVE_TLS_CERT_BASE64 and SERVE_TLS_KEY_BASE64 to something self-signed/PEM that will otherwise not be considered valid.

2. Enable TLS serving in Hydra's config:

   serve:
   +  tls:
   +    enabled: true

3. Create a test client:

   $ hydra create client --skip-tls-verify \
       --name demo-client \
       --secret password123 \
       --grant-type authorization_code,refresh_token \
       --response-type token,code,id_token \
       --scope openid,offline,example.scope \
       --redirect-uri http://127.0.0.1:9010/callback
   

4. Use perform to try and do an authorization-code:

   $ hydra perform --skip-tls-verify authorization-code --port 9010 --client-id 387069d9-9a01-4e53-b72c-507a59f0f4df --client-secret password123 --scope openid,offline,example.scope --skip-tls-verify --auth-url https://127.0.0.1:4444/oauth2/auth

5. Observe failure, as if --skip-tls-verify had not been set at all:
   

6. Apply diff in this PR.

7. It works as you'd expect:
   

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  [email protected]) from the maintainers to push
  the changes.
• I have added or changed the documentation. Not applicable, docs already contained information about this flag; it just didn't work.

Further Comments

Minor change.

[alnr]

Thank you!

We're having some issues with our CI since our move to an internal monorepo. We'll merge this change after that's resolved.