Remove improper use of setSecret for username in OIDC utils

Is your feature request related to a problem? Please describe.

Currently, the code marks the username as a secret using core.setSecret(username) in setOidcStepOutputs (src/oidc-utils.ts). Usernames are generally not sensitive information, and marking them as secrets can result in unnecessary log obfuscation and confusion. User name can be used as part of many other not sensitive names used in the workflow.

Describe the solution you'd like to see

Remove the call to core.setSecret(username) from the setOidcStepOutputs function and only mark truly sensitive values such as tokens and passwords as secrets. If the username is ever sensitive, ensure that is a documented exception.

Describe alternatives you've considered

• Leaving the code as-is, which may lead to unnecessary log redactions for non-sensitive values.
• Adding a comment to clarify when a username should be treated as a secret (if ever).

Additional context

Reference: https://github.com/jfrog/setup-jfrog-cli/blob/29fa5190a4123350e81e2a2e8d803b2a27fed15e/src/oidc-utils.ts#L160

Start in src/oidc-utils.ts at the setOidcStepOutputs function and inspect how the username, tokens, and passwords are handled as secrets. Remove only the username secret marking, preserve protection for sensitive values, and verify the action's existing checks or test suite pass.