Provide a CLI command for updating an app after a grid migration

Description

Coded workflow (Deno) apps installed to a standalone workspace that later gets migrated to an enterprise grid currently need manual intervention to continue working with the CLI. Maybe we want to add a new command like slack app migrate --app=A1234 --enterprise-id=E12345 that would search their .credentials file for an auth token for that enterprise ID, update their local apps.json and reinstall at the org level

Currently, the manual intervention required is to slack login to the new enterprise team which will save the new auth in your ~/.slack/credentials.json file, then update the local .slack/apps.json file in the project to reflect the new enterprise team ID (app ID remains the same as before the migration). Sample below:

{
  "apps": {
    "E12345678": {
      "app_id": "A12345678",
      "enterprise_id": "E12345678",
      "team_domain": "my-domain",
      "team_id": "T98765432"
    }
  },
  "default": "my-domain"
}

🤞 Run slack deploy and if the contents of .slack/apps.json are valid, you should be able to select the app and re-deploy

Requirements

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

Start with the existing slack login and slack deploy entry points, then trace how ~/.slack/credentials.json and .slack/apps.json are read and updated. Define the migration command around an app ID and enterprise ID, and verify that it selects the enterprise token, updates the local app mapping, and enables a subsequent deploy.