fix: `application:get_env/2` returns `{ok, Value}`

[paulswartz]

Ran into this while trying to use max_clock_skew to investigate something else. This didn't appear to be covered by tests, but happy to add them if you can point me in the right direction.

[maennchen]

@paulswartz Good catch.

A test for this would be awesome. We could probably duplicate the retrieve_rs256_with_rotation_test and remove the rotation parts. Instead we can set the nbf / exp fields to slightly expired valuues and use the clock skew to still make it pass.

https://github.com/erlef/oidcc/blob/71896a05aaf7c695a1e66f2fa75e7f1ad77428e1/test/oidcc_token_test.erl#L124

[paulswartz]

@maennchen thank you for the pointer! I ended up using a simpler test example (less to remove!) but let me know if you don't think that works.