fix: expose APIFY_USER_IS_PAYING env var to the configuration

src/apify/_configuration.py

@@ -334,6 +334,15 @@ class Configuration(CrawleeConfiguration):
         ),
     ] = None
 
+    user_is_paying: Annotated[
+        bool,
+        Field(
+            alias='apify_user_is_paying',
+            description='True if the user calling the Actor is paying user',
+        ),
+        BeforeValidator(lambda val: False if val == '' else val),
+    ] = False
+
     web_server_port: Annotated[
         int,
         Field(