Describe the bug
The Spotify Get Playlist action is meant to allow you pass a playlist ID in 2 ways:

1. Using async options and selecting from a list of existing playlists
2. Entering a custom expression or using a variable from a previous step

Only (1) works currently. (2) returns a 400 Bad Request error, as the playlist ID is undefined in the API call to Spotify

To Reproduce
Steps to reproduce the behavior:

1. Add the Spotify Get Playlist action to a workflow and authenticate your account
2. Test the workflow by entering a playlist ID
3. See error

Expected behavior
The call should resolve successfully with a 200 OK response and the playlist I've attempted to fetch

Screenshots
If applicable, add screenshots to help explain your problem. Note that the screenshots will be displayed publicly.

Additional context
Add any other context about the problem here.