Remove trace detail item key

[adamint]

Description

As mentioned in the linked issue, it cannot be assumed that trace span ids are unique. We should remove the key entirely

Fixes #6441

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 don't think this is the right fix. We should reject duplicate span ids that are sent to Aspire. I just added that logic to main branch here:

aspire/src/Aspire.Dashboard/Otlp/Model/OtlpTrace.cs

Lines 55 to 58 in f3a410d

	if (Spans.Contains(span.SpanId))
	{
	throw new InvalidOperationException($"Duplicate span id '{span.SpanId}' detected.");
	}

I'll create a new PR with this fix and test

[JamesNK]

My PR: #6471. Closing this one.