Update GitHub CI Workflow for dispatching PRs

[TerrenceMcGuinness-NOAA]

Description

Small change to global-workflow-ci GitHub Actions file so it can be triggered from a PR via the label CI-Orion-Dispatch or directly on a branch if needed.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Clone and Build tests on WCOSS Dell P3
• Cycled test on Orion
• Forecast-only test on Hera

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• New and existing tests pass with my changes

[aerorahul]

ok.

[WalterKolczynski-NOAA]

Only Orion?

I'm also confused about the label thing. We already have a different label for launching CI from PRs (CI-Orion-Ready). What is the different between the two?