Ensure our custom user agent is flow to auth HTTP calls

[ellismg]

This isn't happening out of the box today - there are two things we need to do:

1. for places where we leverage existing the existing Azure Identity SDK clients, ensure we pass a ClientOptions that installs our UserAgent policy.
2. For places where we use msal directly, also ensure we are setting a user-agent on these requests.

[danieljurek]

https://github.com/Azure/azure-dev/pull/3452/files#r1515083637

If you just want to mark requests as originating from azd, you can set ClientOptions.Telemetry.ApplicationID. That gets a value like azsdk-go-azidentity/v1.6.0-beta.2 (go1.21.6; linux)

[github-actions]

This issue has been automatically marked as stale because it has not had any activity in the last year!!,
and it will be closed in 30 days if no further activity occurs.

If you think this is a mistake, please comment on this issue to keep it open.