ruff: Fix E721 Use `isinstance()` for isinstance checks.

Signed-off-by: Anders Kaseorg <anders@zulip.com>
(cherry picked from commit 05e54a0af2)

corporate/lib/stripe_event_handler.py

@@ -55,7 +55,7 @@ def stripe_event_handler_decorator(
                 "description": e.error_description,
             }
             event.save(update_fields=["status", "handler_error"])
-            if type(stripe_object) == stripe.Invoice:
+            if isinstance(stripe_object, stripe.Invoice):
                 # For Invoice processing errors, send email to billing support.
                 send_email(
                     "zerver/emails/error_processing_invoice",