ActivitySource feature does not allow for meaningful resource names

[lukeemery]

Describe the bug Resource name is always {ActivitySource.Name}.{Activity.OperationName}

Expected behavior Allow for customization by using

{Activity.DisplayName} when {Activity.DisplayName} != {Activity.OperationName}

Doing this would enable me to give more meaningful names, example being POST testapi.orionadvisor.com/api/v1/security/token

Screenshots

Runtime environment (please complete the following information):

• Instrumentation mode: lambda extension
  • arn:aws:lambda:us-east-1:464622532012:layer:Datadog-Extension:25
  • arn:aws:lambda:us-east-1:464622532012:layer:dd-trace-dotnet:5
• CLR: dotnet 6

Additional context Add any other context about the problem here.