`node-version-file` should support absolute paths

Description:

If we pass a absolute path to node-version-file, for example, when using with Composite Actions, the resulting path is resolved incorrectly, due to a path.join() call.

https://github.com/actions/setup-node/blob/5e21ff4d9bc1a8cf6de233a3057d20ec6b3fb69d/src/main.ts#L96-L100

Action version:
v3

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:

Repro steps:

1. In a composite action with .nvmrc, use following as input:

   node-version-file: ${{ github.action_path }}/.nvmrc
   

Example broken action run: https://github.com/sidvishnoi/mediasession/actions/runs/6158104300/job/16710218833?pr=1

Expected behavior:

If it can check whether provided node-version-file exists as is, or perhaps use path.resolve(), it won't break with absolute paths.

Actual behavior:

Error: The specified node version file at: /home/runner/work/mediasession/mediasession/home/runner/work/_actions/w3c/spec-prod/fix-nvmrc/.nvmrc does not exist
                                                                                      ^^^

Start in src/main.ts around lines 96-100, where node-version-file is resolved, and reproduce the composite-action example using an absolute .nvmrc path. Verify that absolute paths are checked without being prefixed again, while relative paths continue to work and the reported missing-file error is resolved.