Consider using another name than Azure SDK Owners ... primary contacts, randomly selected

Looks like `codeownersEntry.ServiceOwners` is being treated similarly to `AzureSDKOwners` here. I wonder if this can be deduplicated under the name `PrimaryContact` vs `ServiceOwners`

_Originally posted by @danieljurek in https://github.com/Azure/azure-sdk-tools/pull/13552#discussion_r2738794206_

Start by tracing the uses of `codeownersEntry.ServiceOwners` and `AzureSDKOwners` mentioned in the issue, and compare how each represents primary contacts. Clarify the intended canonical name and scope with maintainers, then consider the work complete when the terminology is consistently deduplicated and existing references remain correct.

Written by the indexing model from the issue text.