Don't log the token credential until it's used.

[davidfowl]

Description

This change introduced some excess logging every time an azure resource is used. Only log when actually using the credential (as it was before).

Fixes #8905

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
• Are you including unit tests for the changes and scenario tests if relevant?
  • No
• Did you add public API?
  • No
• Does the change make any security assumptions or guarantees?
  • No
• Does the change require an update in our Aspire docs?
  • No