### Problem
The Slack integration fails when fetching channels from workspaces with
many channels due to rate limiting errors. The current implementation
makes a single API call requesting both public and private channels
simultaneously with `types: 'public_channel,private_channel'`, which
causes Slack's API to apply complex filtering and hit rate limits more
frequently.
When testing with a csutomer workspace containing 157 channels:
- Combined request: Hit rate limits after a few pages, required 22+ API
calls with long delays
- Separate requests: Private channels (1 channel) load instantly, public
channels (185 channels) load quickly
### Solution
Split the channel fetching into two sequential steps:
1. **Fetch private channels first** with `limit: 1000` (expects very
few)
2. **Fetch public channels second** with pagination as needed
This approach leverages the fact that Slack's API handles single-type
requests much more efficiently than mixed-type requests, avoiding the
rate limiting issues entirely while maintaining the same functionality.
Fixes
https://linear.app/chatwoot/issue/CW-4507/slack-integration-not-showing-private-channels
## Problem
When the Slack workspace has many channels (requiring multiple API
requests to fetch all of them), our system was only looking for private
channels in the first batch of results. All subsequent batches were
missing the instruction to include private channels, so they only
returned public channels.
## Root Cause
- Initial API call correctly specified `types:
'public_channel,private_channel'`
- Pagination loop only passed `cursor` parameter, omitting `types` and
`exclude_archived`
- Subsequent pages defaulted to public channels only
## Changes
- Fixed parameter formatting in `types` (removed space:
`'public_channel, private_channel'` →
`'public_channel,private_channel'`)
- Added missing `types` and `exclude_archived` parameters to paginated
`conversations_list` calls
---------
Co-authored-by: Sojan Jose <sojan@pepalo.com>
