Create test version of Kusto tables for unofficial pipelines

This is a follow-up to https://github.com/dotnet/dotnet-docker-internal/issues/8105.

With the introduction of official/unofficial pipelines split, we'd like to exercise the `ingestKustoImageInfo` step during unofficial publishing if possible.

https://github.com/dotnet/docker-tools/blob/7841dec2366245a4446a48617e7fbf68b27fa98e/eng/common/templates/jobs/publish.yml#L186-L206

We should have a test Kusto cluster which we can ingest build telemetry to. This will help prevent us from making unexpected breaking changes to the publish stage in our pipelines.

One other idea I had - can we use the Kusto Emulator container image during unofficial builds, or even PR validation/eng validation? https://learn.microsoft.com/en-us/azure/data-explorer/kusto-emulator-overview

Maybe we can even reference it as a [container resource](https://learn.microsoft.com/en-us/azure/devops/pipelines/process/resources?view=azure-devops#containers-resource) so it's available during the pipeline run.