health: Disable RabbitMQ check if not USING_RABBITMQ.

Fixes a spurious error that’s logged and ignored during the Puppeteer
tests, introduced by commit eef65d7e30
(#31438).

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/views/health.py

@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.db.migrations.recorder import MigrationRecorder
 from django.http import HttpRequest, HttpResponse
 from django.utils.crypto import get_random_string
@@ -58,6 +59,7 @@ def check_memcached() -> None:
 
 def health(request: HttpRequest) -> HttpResponse:
     check_database()
+    if settings.USING_RABBITMQ:  # nocoverage
         check_rabbitmq()
     check_redis()
     check_memcached()