ci: fix broken OpenAPI generation

[MIchaelMainer]

Summary

We broke OpenAPI generation with our last dev merge to main.

The changes in this PR include:

• fix so that generated OpenAPI is checked into repo
• update output and step names to add more clarity in logs

Microsoft Reviewers: Open in CodeFlow

• PR for OpenAPI files so that we can review before they are checked in. Important note here is that SDK generation will still occur based on the OpenAPI specs. We will need to make sure that we add reviewing these PRs as part of OCE responsibilities. I did not add PR for CSDL.

[Copilot]

Pull Request Overview

This PR fixes OpenAPI generation that was broken in the previous dev merge to main. The changes enable OpenAPI files to be checked into the repository and introduce PR creation for reviewing OpenAPI changes before they are committed.

Key changes:

• Enhanced git-push-cleanmetadata.ps1 script to support PR creation workflow
• Added comprehensive logging and status checks throughout the process
• Implemented PR creation for OpenAPI files in the capture-openapi.yml pipeline

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
scripts/git-push-cleanmetadata.ps1	Enhanced with PR creation support, improved logging, and better error handling
scripts/create-pull-request.ps1	Fixed variable declaration order issue
.azure-pipelines/generation-templates/capture-openapi.yml	Added PR creation workflow and improved display names for clarity
.azure-pipelines/generation-templates/capture-metadata.yml	Updated to explicitly set CreatePR=False for CSDL metadata

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[MIchaelMainer]

We have successful OpenAPI changes pushed and PRs opened:
microsoftgraph/msgraph-metadata#912
microsoftgraph/msgraph-metadata#913

We have an approval gate for OCE to review OpenAPI before we generate SDKs. See build 201145.