Move dashboard login URL log message last

[JamesNK]

Description

While trying out the standalone dashboard I found that the log message with the login link was hard to find because it was mixed in the middle of other log messages.

This PR moves the login link to the last log message at startup.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
      • Yes
        • Link to aspire-docs issue (please use this breaking-change template):
      • No
        • Link to aspire-docs issue (please use this doc-idea template):
  • No

Microsoft Reviewers: Open in CodeFlow

[JamesNK]

I updated to new VS and got a warning about ambigious overload here between span and string. I believe this is caused by work in the compiler to make span more first class.

Fixed by explicitly calling ToString instead of previously using implicitly string conversion.