Improve annotation for stripe DeletableAPIResource delete method (#7230)

stubs/stripe/@tests/stubtest_allowlist.txt

@@ -0,0 +1,2 @@
+# DeletableAPIResource.delete is has a custom classmethod overload
+stripe\..*\.delete

stubs/stripe/stripe/api_resources/abstract/deletable_api_resource.pyi

@@ -1,4 +1,7 @@
+from _typeshed import Self
+
 from stripe.api_resources.abstract.api_resource import APIResource as APIResource
 
 class DeletableAPIResource(APIResource):
-    def delete(self, **params): ...
+    @classmethod
+    def delete(cls: type[Self], sid: str = ..., **params) -> Self: ...