FDN-4433 Remove add-labels Github workflow

[jackl]

This is now done in the scala-steward repository in the Jenkins pipeline.

Summary by CodeRabbit

• Chores
  • Removed the automated label management workflow that previously handled label assignment and processing for pull requests throughout the repository.
  • Updated auto-merge workflow with tighter conditional requirements: automatic approval and merge operations now require both a successful build state AND successful verification through the specified Jenkins continuous integration branch context, ensuring more precise and controlled execution.

[coderabbitai]

📝 Walkthrough

Walkthrough

A GitHub Actions workflow for automatically adding an "auto-merge" label to PRs with the "scala-steward" label was removed entirely. The auto-merge workflow's approval condition was simultaneously tightened to additionally require a specific Jenkins CI context before executing.

Changes

Cohort / File(s)	Summary
Workflow Removal .github/workflows/add-labels.yml	Entire workflow deleted. Previously triggered on PR events to create and apply "auto-merge" label when "scala-steward" label was present, using GitHub CLI operations.
Auto-Merge Gate .github/workflows/auto-merge.yml	Conditional on approve-and-merge job now requires both github.event.state == 'success' AND github.event.context == 'continuous-integration/jenkins/branch', narrowing execution scope to Jenkins CI context specifically.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: removing the add-labels GitHub workflow file.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[flow-tech]

Click here for code coverage report: https://jenkins.flo.pub/job/flowcommerce/job/lib-akka/job/PR-240/1/scoverage-report/