[bug] Environment variable parsing is inconsistent. ${{ github.action_path }} is different than $GITHUB_ACTION_PATH in `env.GITHUB_ACTION_PATH=${{ github.action_path }}`

The environment variables are parsed differently on the steps than they are inside the script, because the exec step inherits the environment from the parent

This is an excerpt of a run step inside a container I was testing

Essentially, when you use env.GITHUB_ACTION_PATH=${{ github.action_path }} you get a different result in the environment variable as if you used the ${{ github.action_path }} directly. I think this has to do with how the exec script is currently done and streamed. there might need to be some proxy to the variables to imrpote this

  steps:
    - shell: bash
      env:
        GITHUB_ACTION_PATH: ${{ github.action_path }}
        WORKSPACE: ${{ github.workspace }}
      run: |
        echo External ACTION PATH: GITHUB_ACTION_PATH="${GITHUB_ACTION_PATH}"
        echo ACTION PATH INSIDE SCRIPT: ${{ github.action_path }}

        echo External WORKSPACE: WORKSPACE="${WORKSPACE}"
        $ External ACTION PATH: GITHUB_ACTION_PATH=/__w/repo/repo/./actions/linter-configs
        $ ACTION PATH INSIDE SCRIPT: /home/runner/_work/repo/repo/./actions/linter-configs
        $ External WORKSPACE: WORKSPACE=/__w/repo/repo
        $ WORKSPACE INSIDE SCRIPT: /home/runner/_work/repo/repo

Start by tracing how the exec step inherits and streams its environment, then compare the env.GITHUB_ACTION_PATH and inline ${{ github.action_path }} paths in the container run-step example. Done means both forms produce the same path, including for GITHUB_WORKSPACE.