Jira Slack integration's configuration page fails to load if it has subscriptions to more than 50 channels

Problem

If a project has subscriptions to more than 50 channels, it fails to load due to server error caused by hitting the rated limit on Slack side for `conversations.info` method. That method has quite low rate limit - 50 reqs/minute, so it's expected for the app to reach the limit immediately.

Steps to Reproduce

Go to Project > Slack Integration > try to add or edit a current channel integration, errors like below will show up:

"Slack error: something went wrong while getting project connection list. Error ID: <error_id>"
"Error loading subscription details Unable to find the requested subscription. If it still exists it will be in the list below"

The error below can be found in the HAR file:

Request URL:<https://atlassian-slack-integration.services.atlassian.com/api/subscriptions>
Request Method:GET
Status Code:500
Remote Address:104.192.138.7
{ "error": \{ "message": "Something went wrong! Please try again later.", "code": "UNEXPECTED_ERROR", "reqId": "<req_id>", "source": "slack" } }

Expected Results

Be able to add a new or edit channel integration between Jira and Slack via UI using the Slack Integration feature for subscriptions with more than 50 channels already configured with no error.

Actual Results

The page does not load and the "error loading subscription details" message is returned.

Workaround

Manage the connection between a Jira Cloud project and a Slack channel directly from the channel by using the /jira connect and /jira manage commands.