Remove package name approval check from release pipeline (now gated at spec PR level)

## Summary

Remove the APIView-based package name (namespace) approval check from the release pipeline. This check is now redundant — namespace approval is gated at the spec PR level via the new workflow on azure-rest-api-specs (PR Azure/azure-rest-api-specs#44085).

Since spec PRs cannot merge without namespace approval, SDK generation never starts for unapproved namespaces. The release-time check is no longer needed.

## Files to update

- `eng/common/scripts/Validate-All-Packages.ps1` (line ~240)
- Remove `PackageNameApproval.Status` from the blocking condition
- `eng/common/scripts/Validate-Package.ps1`
- Remove `$packageNameStatus` handling and return value
- `eng/common/scripts/Helpers/ApiView-Helpers.ps1`
- Remove package name status code logic (201 vs 202 distinction)
- Simplify `Check-ApiReviewStatus` to only check API review approval
- Remove `Process-ReviewStatusCode` package name branches

## Context

- Namespace approval is now enforced as a merge gate on spec PRs via `namespace-approval.yml` workflow
- The APIView `AutoReviewController` endpoint (200/201/202 status codes) can be simplified to only return API review status
- Related: Azure/azure-rest-api-specs#44085, Azure/azure-sdk#10037

## Acceptance criteria

- [ ] Release pipeline no longer checks package name approval status
- [ ] `Validate-All-Packages.ps1` only blocks on API review approval + changelog + work item
- [ ] APIView endpoint simplified (optional — can be a separate PR)