Unable to authenticate without kid in JWK and JWTs

[wfjsw]

Describe the bug
The RFC7515 and RFC7517 all deems the kid field as optional, but this plugin is unable to authenticate when kid is not present on the JWT and JWKS.

To Reproduce
Steps to reproduce the behavior:

1. Use this plugin to login via a provider that does not have a kid.
2. Set up JWKS url, and it fails.
3. Remove JWKS url, and it restores.

Screenshots
If applicable, add screenshots to help explain your problem.
White screen, with URL saying authentication failed.

Expected behavior
A clear and concise description of what you expected to happen.
The plugin should assume the first key available, or try all keys.

Isolating the problem (mark completed items with an [x]):

• I have deactivated other plugins and confirmed this bug occurs when only this plugin is active.
• This bug happens with a default WordPress theme active.
• I can reproduce this bug consistently using the steps above.

WordPress Environment

• Website URL: https://winterco.org/
• PHP Version: 8.4.11
• WordPress Version: 6.9.1
• Plugin Version: 3.11.3
• Identity Provider: https://seat.winterco.org
• Relevant Plugin Settings: JWKS URI. https://seat.winterco.org/.well-known/jwks