Use a Custom Trace Interop User Agent

[ipbyrne]

It would be nice if our conformance postman tests used a specific user agent so you can filter our requests from that agent when reviewing server request logs.

It currently uses PostmanRuntime/7.29.0, which does help filter out postman requests but would be nice if it was more granular.

[nissimsan]

@ipbyrne , we did this - can you confirm so we can close the issue?

[ipbyrne]

Confirmed this is done!