Upload Windows crash reports on Azure build pipelines for pull requests only

[nathansobo]

To combat hard crashes like #18991, we need access to crash the dumps produced by Electron for a given build on Windows. Crash reports leak environment variables, so we can't upload them as public artifacts on release branches. This PR will enable uploading on non-release branches, and I will follow up with a second PR to upload them to a private location for release branches.

Tasks:

• Initial implementation for Azure build pipelines
• Ensure passing PR builds still succeed when there are no crash reports to publish
• Ensure failing PR builds with no crashes don't produce errors for build steps associated with crash report upload.
• Ensure PR builds can publish crash dumps

[nathansobo]

I'm going to focus just on PR builds for now and focus on release branch builds in a subsequent PR. Updated the body accordingly.

[nathansobo]

I'm going to merge this so we can start getting crash reports on PRs ASAP. A review would still be appreciated though in case I should follow up with any adjustments.

[smashwilson]

For future reference, you're not tied to batch here; you can use powershell to write in PowerShell instead:

- powershell: |
    if (Path-Exists "${env:ARTIFACT_STAGING_DIR}\crash-reports") {
      Create-Item -Type Directory "${env:ARTIFACT_STAGING_DIR}\crash-reports"
    }
    # etc