unit-test: token/services/config

[AkramBitar]

This issue is about increasing the test coverage of the package token/services/config to above 80%.

[nishantbkl3345-ship-it]

Hi, I’d like to work on this issue.

I took a quick look at the token/services/config package and it seems relatively self-contained, so I’ll start by checking the current coverage and identifying any missing test cases around configuration parsing and validation.

I’ll keep the PR focused on improving coverage without touching existing logic. Let me know if there’s any preferred direction before I begin.

[sid200727]

Hi! I recently merged unit tests for the certifier package (#1482) and interop/encoding package and am familiar with the test patterns in this codebase. I've already written and tested the unit tests for configuration.go, opened PR #1543. Happy to be assigned formally, but the work is ready for review.