feat: Improve logging in the oauth2 callback handler

[umi0410]

Fixes #11369

Motivation

The current implementation of the OAuth2 callback handler lacks sufficient logging, making it difficult to identify errors and misconfigurations related to SSO (Single Sign-On). By adding detailed logs, we can simplify the process of configuring SSO and troubleshoot any issues that may arise.

Due to the insufficient logs in the oauth2 callback handler, it wasn't easy to identify the errors and misconfigurations about sso.

If the servers writes detailed logs, it would help the process configuring sso.

Modifications

I have added error logging to the /oauth2/callback handler.

Verification

To verify these changes, I performed the following tests:

1. Test with an incorrect client secret - I set the client secret to foobarbaz, which is an invalid value.

# before
time="2023-07-16T12:04:06.600Z" level=info duration=8.976035ms method=GET path=/oauth2/callback size=0 status=401

# after
time="2023-07-16T12:20:25.064Z" level=error msg="failed to get oauth2Token by using code from the oauth2 server" error="oauth2: \"unauthorized_client\" \"Invalid client secret\""
time="2023-07-16T12:20:25.064Z" level=info duration=9.112831ms method=GET path=/oauth2/callback size=0 status=401

2. Test with an incorrect ID token issuer - I set the issuer to include the unnecessary port (80).

# before
time="2023-07-16T12:08:36.733Z" level=info duration=65.410745ms method=GET path=/oauth2/callback size=0 status=401

# after
time="2023-07-16T12:18:16.333Z" level=error msg="failed to verify the id token issued" error="oidc: id token issued by a different provider, expected \"http://keycloak-http.keycloak:80/auth/realms/myrealm\" got \"http://keycloak-http.keycloak/auth/realms/myrealm\""
time="2023-07-16T12:18:16.333Z" level=info duration=19.251945ms method=GET path=/oauth2/callback size=0 status=401

[terrytangyuan]

This is great! Thanks