Legacy Slack Integration Failing Due to Deprecated API Methods #640

Description

The legacy Slack integration is failing with the following error:

Current Behavior

• The integration is located in src/actions/slack/legacy_slack/
• It's attempting to use deprecated Slack API methods for file uploads
• The error suggests Slack is no longer accepting these API calls

Proposed Solution

There are a few potential fixes:

1. Force V1 upload by setting FORCE_V1_UPLOAD=on environment variable
2. Update the code to use Slack's V2 file upload API methods
3. Create a new, modern Slack integration using current Slack API methods

Additional Context

• This appears to be affecting the file upload functionality specifically
• The integration has both V1 and V2 upload code paths, but neither are working with current Slack API requirements
• The error message indicates a mismatch between required and accepted scopes

Impact

Users are unable to upload files to Slack through this integration, breaking existing workflows.

Questions

1. Should we maintain the legacy integration or create a new one?
2. If maintaining, which approach (V1 force or V2 upgrade) would be preferred?
3. Are there any existing plans to replace this legacy integration?