chore(slack): Add Ignore Transaction Boundary in SDK Client for Tests (…

…#73582)

The old SDK client had some logic to ignore transaction boundaries when
using an RPC call to fetch the integration when running tests (the
function doesn't do anything in production).

https://github.com/getsentry/sentry/blob/master/src/sentry/incidents/serializers/alert_rule.py#L481-L488

This is required because in some parts of our code, we use the SDK
Client within a transaction such as here:

https://github.com/getsentry/sentry/blob/master/src/sentry/incidents/serializers/alert_rule.py#L481-L488

This is safe to do because the RPC call is a read operation.

Without this function, we run into 
```
E   AssertionError: remote service method to /api/0/internal/rpc/integration/get_integration/ called inside transaction!  Move service calls to outside of transactions.
```
when running tests that go through the above mentioned transaction code
path.

src/sentry/integrations/slack/sdk_client.py

@@ -6,6 +6,7 @@
 from slack_sdk.errors import SlackApiError
 from slack_sdk.web import SlackResponse
 
+from sentry.db.postgres.transactions import in_test_hide_transaction_boundary
 from sentry.integrations.base import disable_integration, is_response_error, is_response_success
 from sentry.integrations.request_buffer import IntegrationRequestBuffer
 from sentry.integrations.services.integration import integration_service
@@ -111,7 +112,14 @@ def __init__(self, integration_id: int):
 
         integration: Integration | RpcIntegration | None
         if SiloMode.get_current_mode() == SiloMode.REGION:
-            integration = integration_service.get_integration(integration_id=integration_id)
+            """
+            # In order to send requests, SlackClient needs to fetch the integration
+            # to get access tokens which trips up rpc method/transaction
+            # boundary detection. Those boundaries are not relevant because
+            # this is a read operation.
+            """
+            with in_test_hide_transaction_boundary():
+                integration = integration_service.get_integration(integration_id=integration_id)
         else:  # control or monolith (local)
             integration = Integration.objects.filter(id=integration_id).first()