Don't send request for permalink if slack token has been revoked (#4777)

# What this PR does
Don't send request for permalink if slack token has been revoked

## Which issue(s) this PR closes

Related to https://github.com/grafana/oncall-private/issues/2843

## Checklist

- [x] Unit, integration, and e2e (if applicable) tests updated
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] Added the relevant release notes label (see labels prefixed w/
`release:`). These labels dictate how your PR will
    show up in the autogenerated release notes.

engine/apps/slack/models/slack_message.py

@@ -82,7 +82,8 @@ class SlackMessage(models.Model):
 
     @property
     def permalink(self) -> typing.Optional[str]:
-        if self.cached_permalink or not self.slack_team_identity:
+        # Don't send request for permalink if there is no slack_team_identity or slack token has been revoked
+        if self.cached_permalink or not self.slack_team_identity or self.slack_team_identity.detected_token_revoked:
             return self.cached_permalink
 
         try:

engine/apps/slack/test_slack_message.py

@@ -1,6 +1,7 @@
 from unittest.mock import patch
 
 import pytest
+from django.utils import timezone
 
 from apps.slack.client import SlackClient
 from apps.slack.errors import SlackAPIError
@@ -60,3 +61,18 @@ def test_slack_message_permalink_cache(mock_slack_api_call, slack_message_setup)
     slack_message = slack_message_setup(cached_permalink="cached_permalink")
     assert slack_message.permalink == "cached_permalink"
     mock_slack_api_call.assert_not_called()
+
+
+@patch.object(
+    SlackClient,
+    "chat_getPermalink",
+    return_value=build_slack_response({"ok": False, "error": "account_inactive"}),
+)
+@pytest.mark.django_db
+def test_slack_message_permalink_token_revoked(mock_slack_api_call, slack_message_setup):
+    slack_message = slack_message_setup(cached_permalink=None)
+    slack_message._slack_team_identity.detected_token_revoked = timezone.now()
+    slack_message._slack_team_identity.save()
+    assert slack_message._slack_team_identity is not None
+    assert slack_message.permalink is None
+    mock_slack_api_call.assert_not_called()