Only add double-dash to args if there are previous app-host-added args

[Adam Ratzman (adamint)]

Description

It doesn't appear that a double-dash is required to be prepended to application launch args when there are no app host arguments. Mitch Denny (@mitchdenny) does this make sense?

Fixes #7751

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

[Copilot]

Copilot reviewed 1 out of 1 changed files in this pull request and generated no comments.

[Mitch Denny (mitchdenny)]

Correct. They should be unncessary.

[Mitch Denny (mitchdenny)]

Why not just do the check internally to the method.

[Mitch Denny (mitchdenny)]

Please do some testing with this in the playground just to make sure there are no rough edges here.

[James Newton-King (JamesNK)]

Even if there are previous app host added args, the double dash could be excluded from what is displayed to the user by not adding it to the custom annotation.

This is a suggested improvement.