What does this PR do?

This PR introduces a new Smartsheet piece to Activepieces, enabling users to automate workflows by connecting Smartsheet with other applications. It includes actions for managing rows and attachments, comprehensive search capabilities, and real-time webhook-based triggers for various sheet events.

Explain How the Feature Works

The Smartsheet piece allows users to:

• Actions: Create/update rows, attach files, and search sheets/rows/attachments.
• Triggers: React in real-time to new rows, updated rows, new attachments, or new comments using Smartsheet webhooks.

Authentication is via Smartsheet API Access Token.

Relevant User Scenarios

• Automate task creation in Smartsheet from form submissions.
• Sync Smartsheet row updates to a CRM or database.
• Process new Smartsheet attachments (e.g., save to cloud storage).
• Notify teams about new comments on critical Smartsheet items.

Fixes #7921 /claim #7921