Add client debug line that prints the selected token

[brianhlin]

Pelican Service:

• Client
• Plugin
• Registry
• Director
• Origin
• Cache
• Other (please give the detail)

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

I'm trying to troubleshoot a permission denied issue where the client has access to multiple tokens and it's unclear which token Pelican is choosing for the transfer

DEBUG[2025-04-18T14:20:05-05:00] Out of token locations to search             
WARNING[2025-04-18T14:20:05-05:00] Using provided token even though it does not appear to be acceptable to perform transfer 

Describe the solution you'd like

Update the log message to say Using provided token (<path to token>)...