Allow Configuration of Self-installer Settings

I am running into an issue where I need to pass some settings to the self-installer. Specifically, I am trying to pass --fetch-retries 5 since I am running into 429 (Too Many Requests) errors. I see on the documentation that there's a way to pass args in for the run_install function, so hopefully it won't be too difficult to add them for the self-installer bit.

Here's my code (yes, I'm using v4 of the action):

- uses: pnpm/action-setup@v4
        name: Install pnpm
        with:
          version: 9.7.0

Here's my current log output:

Run pnpm/action-setup@v4
  with:
    version: 9.7.0
    dest: ~/setup-pnpm
    run_install: null
    package_json_file: package.json
    standalone: false
  env:
    ...

Running self-installer...
   WARN  GET https://[AWS CodeArtifact Url] error (429). Will retry in 10 seconds. 2 retries left.
   WARN  GET https://[AWS CodeArtifact Url] error (429). Will retry in 1 minute. 1 retries left.
   ERR_PNPM_FETCH_429  GET https://[AWS CodeArtifact Url]: Too Many Requests - 429
  
  This error happened while installing a direct dependency of /home/runner/setup-pnpm
Error: Something went wrong, self-installer exits with code 1
Installation Completed!

Start by tracing how the self-installer is invoked and compare it with the documented run_install function arguments. Confirm how the action input could carry settings such as --fetch-retries, then verify that the self-installer uses them and that the reported 429 installation case is covered.