Remove instances of ARM private decorator use in azure-rest-api-specs

There are a few instances where folks have used private decorators, We should try to remove each of these. We can look for suppressions of "@azure-tools/typespec-azure-core/no-private-usage"

Search the repository for suppressions of "@azure-tools/typespec-azure-core/no-private-usage" and inspect each matching instance. Remove the private decorator uses and their related suppressions where appropriate, then run the repository's available validation checks. Done means the identified private decorator usages have been removed without introducing validation failures.

Written by the indexing model from the issue text.