Fail http-client-csharp publish pipeline on step errors in manual runs

[Copilot]

In packages/http-client-csharp/eng/pipeline/publish.yml, manual runs currently downgrade step failures to warnings (SucceededWithIssues) and still open a PR in azure-sdk-for-net, giving reviewers a false positive. Manual runs should instead fail the pipeline.

Changes

• Submit-AzureSdkForNetPr.ps1
  • Added -BuildReason parameter; sets $FailOnError when it equals 'Manual'.
  • Added Register-StepFailure helper that records each downgraded failure and preserves the existing ##vso[task.complete result=SucceededWithIssues;] signal.
  • Routed all previously swallowed failures through it — npm install/build, Generate.ps1, sparse-checkout expansion, Azure/mgmt generator builds, and per-service code generation (including their catch counterparts).
  • Before commit/PR creation, throws a summary of failures when $FailOnError is set; the existing outer catch converts this to exit 1, so no PR is opened.
• publish.yml: passes -BuildReason '$(Build.Reason)'.

Automated (scheduled/CI/main) runs are unchanged — they continue reporting SucceededWithIssues and proceed.

$FailOnError = $BuildReason -eq 'Manual'
# ...steps use Register-StepFailure instead of Write-Warning + SucceededWithIssues...
if ($FailOnError -and $script:StepFailures.Count -gt 0) {
    $failureSummary = ($script:StepFailures | ForEach-Object { "- $_" }) -join [Environment]::NewLine
    throw "One or more steps failed during a manual run; not creating a pull request:$([Environment]::NewLine)$failureSummary"
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
1 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@typespec/http-client-csharp@11277

commit: ed6754f