Reject spans that create a circular loop

[JamesNK]

Description

Spans have a parent. A span is not allowed reference itself or one of its anscetors as a parent.

Data sent to the dashboard could contain an invalid circular reference. Rendering the bad data in the UI could cause errors. This PR adds validation logic when spans are received to reject the bad data.

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
    • Link to aspire-docs issue:
  • No

Microsoft Reviewers: Open in CodeFlow

[JamesNK]

I think the changes are too broad to add to 9.0. Can be merged for vnext.

[JamesNK]

PR feedback addressed.