[Feature Request]: Implement LoadScriptFile in ACTION JavaScript the same way already exists in PIPELINE

### What would you like to happen?

We have some common functions that are shared by several workflows, so we like store them in a external .js file and call them as needed the same way we already do with pipelines.

### Issue Priority

Priority: 3

### Issue Component

Component: Actions

Start by locating the existing LoadScriptFile implementation for PIPELINE and the ACTION JavaScript entry point, then compare how each handles an external .js file. Done means ACTION JavaScript supports the same external-file usage described in the request and the relevant project tests pass.

Written by the indexing model from the issue text.