Enhancement proposal: Support for team_id in Slack Notification Configuration

[viacheslav-klimov]

Summary

ArgoCD currently does not allow specifying a team_id in the Slack notification configuration. This limitation prevents the use of Slack org-level applications for notifications, which are essential for organizations with multiple workspaces under a single application.

Motivation

Now you have to create many Slack Webhooks to send messages to different channels of different organizations (team_id). But Slack support slack app delivery method when we use single credentials to send messages to different channels of different organizations.

Proposal

Add optional field team_id on slack notifier configuration.